Chapter+Two

Dmitri Mendeleev BIOL 160: General Biology
 * CHAPTER 2: Life’s Chemical Basis **

Definition Worksheet #2: Chapter 2 Define the following key terms. 1. Atom - particles that are the building blocks of all substances 2. Proton - positive subparticle in the nucleus 3. Neutron - neutral subparticle in the nucleus 4. Electron - negatative subparticle outside of nucleus 5. Atomic Number - number of protons in atom 6. Atomic Mass - total number of protons and neutrons in the nucleus 7. Isotope - an element that has a different number of neutrons 8. Ion - an atom with a different number of electrons 9. Cation - positive ion 10. Anion - negative ion 11. Molecule - two or more atoms combined together 12. Chemical Bond - an attractive force between two atoms when electrons interact <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">13. Ionic Bond - a strong mutual attraction of two oppositely charged ions <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">14. Electronegativity - a measure of an atoms ability to pull electrons from other atoms <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">15. Polar Covalent Bond - covalent bonds that do not share electrons equally <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">16. Non-polar Covale nt Bond - covalent bonds that do share electrons equally <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">17. Hydrogen Bond - wear attraction between a highly electronegative atom and a hydrogen atom taking part in seperate polar covalent bonding <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">18. Solution - a liquid mixture in which the solute is uniformly distributed within the solvent

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">19. Solute - dissolved substance <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">20. Solvent - substance that does the dissolving <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">21. Acid - donates hydrogen atoms as they dissolve <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">22. Base - accepts hydrogen atoms <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">23. Buffer - set of chemicals that keep pH stable <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">24. Salt - a compound that dissolves easily in water and releases ions other than H+ and OH-

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Characteristics of atoms
 * __<span style="font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%;">CHAPTER 2 __****<span style="font-family: 'Times New Roman','serif'; font-size: 14pt; line-height: 115%;">: Basic Introduction to Chemistry **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Subatomic particle || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Charge || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Location || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Mass ||
 * proton || positive || nucleus || 1 amu ||
 * neutron || neutral || nucleus || 1 amu ||
 * electron || negative || outside nucleus || 0.0005 amu ||

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Recent discoveries have increased the number of naturally occurring elements from 92 to 94.

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Since subatomic particles may be **charged**, they may attract or repel other subatomic particles. Please complete the below table, indicating how the below pairings of subatomic particles would behave (attract, neutral, repulsion).
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Subatomic particle || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Proton || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Neutron || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Electron ||
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Proton || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">repulsion || neutral || attraction ||
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Neutron || neutral || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">neutral || neutral ||
 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Electron || <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">attraction || neutral || repulsion ||

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">What is an element? pure substances each consisting only of atoms with the same number of protons


 * Atomic Number= # of protons ||

<span style="font-family: 'Times New Roman','serif';">The periodic table of elements has elements placed in a repeating pattern <span style="font-family: 'Times New Roman','serif';">based on their //chemical properties// and how they react with other
 * <span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">1. ** **<span style="font-family: 'Times New Roman','serif';">Periodic Table **

mass of protons + neutrons || <span style="font-family: 'Times New Roman','serif';">elements. (Appendix 4 in the back of the book shows a periodic table.)
 * Atomic Mass=


 * <span style="font-family: 'Times New Roman','serif';">Principle || <span style="font-family: 'Times New Roman','serif';">Definition || <span style="font-family: 'Times New Roman','serif';">C || <span style="font-family: 'Times New Roman','serif';">N || <span style="font-family: 'Times New Roman','serif';">O || <span style="font-family: 'Times New Roman','serif';">P || <span style="font-family: 'Times New Roman','serif';">F || <span style="font-family: 'Times New Roman','serif';">Na ||
 * <span style="font-family: 'Times New Roman','serif';">Atomic Number || number of protons || 6 || 7 || 8 || 15 || 9 || 11 ||
 * <span style="font-family: 'Times New Roman','serif';">Atomic Mass || number of protons and neutrons || 12 || 14 || 16 || 31 || 18 || 23 ||
 * <span style="font-family: 'Times New Roman','serif';"># of electrons || negative subatomic particles outside the nucleus || 6 || 7 || 8 || 15 || 9 || 11 ||
 * <span style="font-family: 'Times New Roman','serif';"># of protons || positive subatomic particles inside the nucleus || 6 || 7 || 8 || 15 || 9 || 11 ||

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">2. <span style="font-family: 'Times New Roman','serif';">What makes Carbon different than Hydrogen? The number of protons <span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">3. <span style="font-family: 'Times New Roman','serif';">What is an isotope? an atom with the same number of protons but different number of neutrons

<span style="font-family: 'Times New Roman','serif';">A. The element carbon has 3 main different isotopes: <span style="font-family: 'Times New Roman','serif';"> 12C has a mass of 12, due to 6 __protons and__ 6neutrons <span style="font-family: 'Times New Roman','serif';"> 13C has a mass of 13, due to 6 __protons and 7__ neutrons <span style="font-family: 'Times New Roman','serif';"> 14C has a mass of 14, due to 6 __protons and 8__ neutrons <span style="font-family: 'Times New Roman','serif';">B. Some isotopes have an unstable nucleus and may release energy or some of the subatomic particles (protons or neutrons) to become more stable. These isotopes <span style="font-family: 'Times New Roman','serif';">are called **radioisotopes**. Some are used in medicine to “label” specific molecules or to follow a specific molecule as it is distributed throughout the body. In this case it is commonly called a **radioactive tracer**. They may also release enough energy to kill cells and stop the activity of abnormal (cancer) cells, or the energy released may be used to drive an artificial pacemaker (helps the heart maintain a regular rhythm). <span style="font-family: 'Times New Roman','serif';">5. It is most important to know what the subatomic particles are, where they are located in an atom, and that atoms of different elements differ because they contain different numbers of protons. The number behind each elemental name represents the atomic mass for that atom. Complete the following table.
 * //<span style="font-family: 'Times New Roman','serif';">Element // || //<span style="font-family: 'Times New Roman','serif';">Symbol // || //<span style="font-family: 'Times New Roman','serif';">Atomic Number // || //<span style="font-family: 'Times New Roman','serif';">Atomic Mass // || //<span style="font-family: 'Times New Roman','serif';">Number of Protons // || //<span style="font-family: 'Times New Roman','serif';">Number of Neutrons // || //<span style="font-family: 'Times New Roman','serif';">Number of Electrons // ||
 * <span style="font-family: 'Times New Roman','serif';"> Nitrogen-14 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">N || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">7 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">14 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">7 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">7 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">7 ||
 * <span style="font-family: 'Times New Roman','serif';"> Chlorine-35 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">Cl || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">17 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">35 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">17 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">18 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">17 ||
 * <span style="font-family: 'Times New Roman','serif';"> Oxygen-16 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">O || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">16 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 ||
 * <span style="font-family: 'Times New Roman','serif';"> Sodium-23 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">Na || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">11 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">23 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">11 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">12 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">11 ||
 * <span style="font-family: 'Times New Roman','serif';"> Sulfur-35 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">S || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">16 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">35 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">16 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">19 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">16 ||
 * <span style="font-family: 'Times New Roman','serif';"> Oxygen-17 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">O || 8 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">17 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 || <span style="display: block; font-family: Times New Roman,serif; text-align: center;">9 || <span style="display: block; font-family: 'Times New Roman','serif'; text-align: center;">8 ||

<span style="font-family: 'Times New Roman','serif';">6. Complete the following matching activity.
 * <span style="font-family: 'Times New Roman','serif';">A. || <span style="font-family: 'Times New Roman','serif';">Radioisotope used to reveal the pathway or destination of a substance ||
 * <span style="font-family: 'Times New Roman','serif';">B. || <span style="font-family: 'Times New Roman','serif';">Subatomic particles with a negative charge ||
 * <span style="font-family: 'Times New Roman','serif';">C. || <span style="font-family: 'Times New Roman','serif';">Positively charged subatomic particles within the nucleus ||
 * <span style="font-family: 'Times New Roman','serif';">D. || <span style="font-family: 'Times New Roman','serif';">Subatomic particles within the nucleus carrying no charge ||
 * <span style="font-family: 'Times New Roman','serif';">E. || <span style="font-family: 'Times New Roman','serif';">Atoms of a given element that differ in the number of neutrons ||
 * <span style="font-family: 'Times New Roman','serif';">F. || <span style="font-family: 'Times New Roman','serif';">The number of protons in an atom ||
 * <span style="font-family: 'Times New Roman','serif';">G. || <span style="font-family: 'Times New Roman','serif';">Form of an element that emits radiation ||
 * <span style="font-family: 'Times New Roman','serif';">H. || <span style="font-family: 'Times New Roman','serif';">The number of protons and neutrons in the nucleus of one atom ||
 * <span style="font-family: 'Times New Roman','serif';">I. || <span style="font-family: 'Times New Roman','serif';">Pure substances, each consisting only of atoms with the same number of protons ||
 * <span style="font-family: 'Times New Roman','serif';">J. || <span style="font-family: 'Times New Roman','serif';">Smallest units of an element that retain the properties of a given element. Particles that are the building blocks of all substances. ||

<span style="font-family: 'Times New Roman','serif';">1. __atoms (J)__ __<span style="font-family: 'Times New Roman','serif';">2. __ protons (C) <span style="font-family: 'Times New Roman','serif';">3. __neutrons (D)__ __<span style="font-family: 'Times New Roman','serif';">4. __ electrons (B) <span style="font-family: 'Times New Roman','serif';">5. __atomic number (F)__ __<span style="font-family: 'Times New Roman','serif';">6. __ atomic mass (H) <span style="font-family: 'Times New Roman','serif';">7. __elements (I)__ __<span style="font-family: 'Times New Roman','serif';">8. __ isotope (E) <span style="font-family: 'Times New Roman','serif';">9. __radioisotopes (G)__ __<span style="font-family: 'Times New Roman','serif';">10. __ tracer (A)

<span style="font-family: 'Times New Roman','serif';">7. Chemical Bonds <span style="font-family: 'Times New Roman','serif';">Which subatomic particle participates in bonding between atoms? Electrons

<span style="font-family: 'Times New Roman','serif';">How do you figure out how many electrons there are in an atom? <span style="font-family: 'Times New Roman','serif';">The number of electrons is equal to the number of protons in an atom.

<span style="font-family: 'Times New Roman','serif';">B. Each horizontal row on the periodic table represents an energy level around the nucleus of an atom. <span style="font-family: 'Times New Roman','serif';"> 1.The first level is closest to the nucleus and can hold only 2 electrons due <span style="font-family: 'Times New Roman','serif';"> to its small volume and the fact that electrons repel each other. Electrons in this level have the **lowest amount of energy**. Notice that the top row on the periodic table has only two elements (H and He) and the atomic number of Helium is 2 which means it has 2 protons and 2 electrons. <span style="font-family: 'Times New Roman','serif';"> 2. The second level is farther away from the nucleus, so is larger in volume and can hold a __maximum__ of 8 electrons. Notice that the second row on the periodic table has a total of eight elements and the atomic number for Neon the last element on the row is 10; which means a neutral Neon atom has 10 protons and 10 electrons (two of the electrons are on the first energy level and the remaining 8 electrons on the second level). <span style="font-family: 'Times New Roman','serif';"> 3. The third level is still farther away from the nucleus, so is able to hold more electrons than the second level, and the fourth level more than the third, etc. The problem is that not all of these additional electrons are located on the outermost energy level. <span style="font-family: 'Times New Roman','serif';">C. **The atomic number on the periodic table equals the __total__ number of protons inside the nucleus and therefore the __total__ number of electrons found moving around the nucleus in an atom**; however it is **only those electrons on the outer energy level that are taken, shared or given away when atoms interact with other atoms**. The maximum number of electrons that can exist on the outer energy level of __any__ atom is __ALWAYS__ eight (except for H and He where the maximum number is two). Try to remember that “eight is great”. For the purposes of this class and to best prepare you for Anatomy and Physiology, it is necessary to “simplify” chemistry and the periodic table. It will be easier to understand how atoms behave if you pretend that the center (and bottom) of the periodic table don’t exist. Those elements in the middle of the periodic table have additional electrons that are NOT placed in the outer most energy level, therefore they do NOT influence how an atom of that element behaves.

<span style="font-family: 'Times New Roman','serif';">**If this is the case, then all of the horizontal rows on the table will have eight columns**, except the first horizontal row which will have only two columns. <span style="font-family: 'Times New Roman','serif';">D. **Where** the elements are found on the periodic table will help determine how an atom will interact with other atoms (“take”, “share” or “give away” some of their electrons). The **vertical** column of the periodic table indicates **the number of electrons** an atom of that element has in the outermost energy level. As mentioned, **it is only these outermost electrons that will influence how an atom interacts with other atoms as they form molecules**. <span style="font-family: 'Times New Roman','serif';">E. Those elements in the last column on the periodic table (farthest to the right, or in column #8) are the most “stable” of all the elements, having just the right number of electrons to “fill” the outer energy level. These elements are very stable and normally do not react chemically with the other elements to form molecules. (Called the Inert Gases) <span style="font-family: 'Times New Roman','serif';">F. All the other elements on the periodic table “wish” they could have the same number of electrons as one of those in column #8 (farthest to the right) so they too can become very stable. They do this by taking, giving or sharing electrons to fill their outer electron shell. <span style="font-family: 'Times New Roman','serif';">The ability of an atom to “pull or take” electrons from another atom to become more stable is called ELECTRONEGATIVITY. <span style="font-family: 'Times New Roman','serif';">1. Those elements on the **right** side of the periodic table are so close to the last column, they tend to have **high electronegativity** values and tend to “TAKE” electrons from other elements until they have a total of 8 in their outer energy level or in some cases they may be forced to share electrons with other atoms. Using the periodic table as a guide, how many more electrons do atoms of the following elements need to take or share to reach a total of those in the last column? <span style="font-family: 'Times New Roman','serif';"> P =3, Cl =1 , O =2 , N =3 , S =2 , C =4 , Br =1

<span style="font-family: 'Times New Roman','serif';">2. Those elements on the **left side** of the periodic table are far away from the last column, they tend to have **very low electronegativity** values and do NOT “pull or take” electrons from other atoms, in fact they **tend to “GIVE AWAY”** their electrons that are on the outer energy level to other atoms. In a sense they go backwards on the table until they reach the last column but on the row above where they started. Using the periodic table as a guide, how many electrons do atoms of the following elements **need to give away or lose** to revert back to the end of the previous level on the periodic table? <span style="font-family: 'Times New Roman','serif';"> Na =1, Al =3 , Ca =2 , K =1 , C =4 , Mg = 2

<span style="font-family: 'Times New Roman','serif';"> G. Neutral atoms that “take” or “give away” electrons no longer remain neutral; they <span style="font-family: 'Times New Roman','serif';"> become either negatively or positively charged particles called ions__. There are two main types:__ __<span style="font-family: 'Times New Roman','serif';">1. ANIONS are those that have a negative charge because the neutral atom has “taken” electrons from other atoms so they now have more electrons than protons. __ __<span style="font-family: 'Times New Roman','serif';">2. CATIONS are those that have a positive charge because the neutral atom has “given away” electrons to other atoms so they now have fewer electrons than protons. __ __<span style="font-family: 'Times New Roman','serif';">8. When atoms “give away”,” take” or “share” electrons with other atoms they form a __ __<span style="font-family: 'Times New Roman','serif';"> CHEMICAL BOND __ (a force between two atoms that holds them together). <span style="font-family: 'Times New Roman','serif';"> A. Molecules are two or more atoms that have joined together to form a group. Some only contain one type of element: H2, O2, N2, F2, Cl2, Br2 & I2, but the majority contain two or more different types of elements. When a molecule contains two or more different elements combined in a fixed ratio (proportion) that never varies it is called a __. Examples include: water (H2O), Carbon dioxide (CO2), Hydrochloric acid (HCl), and Glucose (C6H12O6). The numbers in the chemical formulas indicate the number of atoms of each type in the molecule.__ __<span style="font-family: 'Times New Roman','serif';"> B. __ Mixtures contain two or more substances (elements or compounds) that are combined together in a ratio (proportion) that **varies.** They can either be concentrated or dilute (as in strong or weak coffee). These forms of matter will be studied in much more detail in future modules. <span style="font-family: 'Times New Roman','serif';">9. There are several important chemical bonds seen in biological molecules. <span style="font-family: 'Times New Roman','serif';">A.IONIC BONDS: oppositely charged ions held close by attraction, electrons transferred (one loses, one gains) between atoms
 * <span style="font-family: 'Times New Roman','serif';">Element Location || <span style="font-family: 'Times New Roman','serif';">Giver? Taker? || <span style="font-family: 'Times New Roman','serif';">What type of ion formed? || <span style="font-family: 'Times New Roman','serif';">Positive or negatively charged ion? ||
 * <span style="font-family: 'Times New Roman','serif';">Left side of per table || Giver || Anion || Positive ||
 * <span style="font-family: 'Times New Roman','serif';">Right side of per. table || Taker || Cation || Negative ||

<span style="font-family: 'Times New Roman','serif';">1. Chemical formulas represent the **type and number of atoms** present in the compound. The number of atoms needed to keep the molecule neutral is dependent on the ion charges. Elements that “give away” one electron form +1 ions, those that “give away” 2 electrons form +2 ions, etc. Elements that “take” one electron form -1 ions, those that “take” 2 electrons form -2 ions, etc. Some examples of chemical formulas for ionic compounds include: <span style="font-family: 'Times New Roman','serif';"> Sodium chloride: NaCl This compound contains Na+1 and Cl-1 ions in a 1:1 ratio since their ion charges are the same value (+1 / -1) and they cancel each other out when forming a neutral atom. <span style="font-family: 'Times New Roman','serif';"> Magnesium nitride: Mg3N2 This compound contains Mg+2 and N-3 ions in a 3:2 ratio since their ion charges do not directly cancel each other out; three Mg+2 ions are needed to make a total of +6 charge, which is cancelled out by two N-3 ions that make a total of -6 charge forming a neutral molecule. <span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">B. <span style="font-family: 'Times New Roman','serif';"> COVALENT BONDS: <span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">1. <span style="font-family: 'Times New Roman','serif';">What is a covalent bond? A chemical bond in which two atoms share a pair of electrons.

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">2. <span style="font-family: 'Times New Roman','serif';">Atoms with (similar, differing) electronegativities form covalent bonds. <span style="font-family: 'Times New Roman','serif';">Covalent Bond ||
 * <span style="font-family: 'Times New Roman','serif';">Covalent Bond || <span style="font-family: 'Times New Roman','serif';"># of electrons shared? || <span style="font-family: 'Times New Roman','serif';">Example || <span style="font-family: 'Times New Roman','serif';">Structural Formula || <span style="font-family: 'Times New Roman','serif';">Strength ||
 * <span style="font-family: 'Times New Roman','serif';">Single || 2 || Hygrogen || H-H || <span style="font-family: 'Times New Roman','serif';">Strong ||
 * <span style="font-family: 'Times New Roman','serif';">Double || 4 || Oxygen || O=O || <span style="font-family: 'Times New Roman','serif';">Stronger ||
 * <span style="font-family: 'Times New Roman','serif';">Triple || 6 || Nitrogen || N\\\N || <span style="font-family: 'Times New Roman','serif';">Stronger yet! ||
 * <span style="font-family: 'Times New Roman','serif';">Between two identical atoms || <span style="font-family: 'Times New Roman','serif';">2 || <span style="font-family: 'Times New Roman','serif';">H2 || H-H || <span style="font-family: 'Times New Roman','serif';">NONPOLAR Covalent Bond ||
 * <span style="font-family: 'Times New Roman','serif';">Between two different atoms || <span style="font-family: 'Times New Roman','serif';">4 || <span style="font-family: 'Times New Roman','serif';">H2O || H-O-H || <span style="font-family: 'Times New Roman','serif';">POLAR

More electrons in Oxygen, so that part of the molecule is more negatively charged; fewer electrons near Hydrogens, so that part of the molecule is less negatively charged ||
 * POLAR COVALENT BOND

<span style="font-family: 'Times New Roman','serif';">3. Covalent bonds are the strongest type of all chemical bonds. They are very difficult to break, and hold atoms together to form molecules. These bonds are also called INTRAMOLECULAR forces, because they exist within the molecule. <span style="font-family: 'Times New Roman','serif';">4. Chemical formulas of compounds that have covalent bonds are determined much the same way that ionic compounds are determined; however both atoms want to “take” electrons from each other. The number of atoms needed to keep the molecule neutral is dependent on the number of electrons they need to be like elements in column #8 on the periodic table. Some examples of chemical formulas for covalent compounds include:
 * <span style="font-family: 'Times New Roman','serif';">Water (H2O) || <span style="font-family: 'Times New Roman','serif';"># of e-s in outer shell || <span style="font-family: 'Times New Roman','serif';">What combo would form an outer shell with 8 e-s? || <span style="font-family: 'Times New Roman','serif';">Draw molecule ||
 * <span style="font-family: 'Times New Roman','serif';">Hydrogen || 1 || H-O-H ||^  ||
 * <span style="font-family: 'Times New Roman','serif';">Oxygen || 6 || H-O-H ||^  ||
 * <span style="font-family: 'Times New Roman','serif';">Carbon Dioxide (CO2) || <span style="font-family: 'Times New Roman','serif';"># of e-s in outer shell || <span style="font-family: 'Times New Roman','serif';">What combo would form an outer shell with 8 e-s? || <span style="font-family: 'Times New Roman','serif';">Draw molecule ||
 * <span style="font-family: 'Times New Roman','serif';">Carbon || 4 || O=C=O ||^  ||
 * <span style="font-family: 'Times New Roman','serif';">Oxygen || 6 || O=C=O ||^  ||

<span style="font-family: 'Times New Roman','serif';">C. HYDROGEN BONDS: <span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">1. <span style="font-family: 'Times New Roman','serif';"> What is a hydrogen bond? <span style="font-family: 'Times New Roman','serif';">An attraction that forms between a covalently bonded hydrogen atom and an electronegative atom taking part in a separate covalent bond.

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">2. <span style="font-family: 'Times New Roman','serif';"> Are hydrogen bonds weak or strong attractions? They are weak attractions due to having only one positively charged ion. They break and form easier than covalent bonds.

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">7. <span style="font-family: 'Times New Roman','serif';">Water’s Life-Giving Properties <span style="font-family: 'Times New Roman','serif';">This illustration shows how hydrogen bonds collectively stabilize water molecules. How does this affect the unique physical properties of water?

<span style="font-family: 'Times New Roman','serif';">a. Water is a molecule held together with POLAR COVALENT BONDS. Draw a picture of a water molecule, and explain how the oxygen and hydrogens participate in this type of bond.

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">b. <span style="font-family: 'Times New Roman','serif';"> Which part of a water molecule is slightly negative?

<span style="font-family: 'Times New Roman','serif';">c. Which is partially positive?

<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">d. <span style="font-family: 'Times New Roman','serif';"> How does this affect interaction with other nearby molecules of water? Or other types of molecules?

<span style="font-family: 'Times New Roman','serif';">e.Why does water have such a high surface tension?

<span style="font-family: 'Times New Roman','serif';">f. What is a solvent?

<span style="font-family: 'Times New Roman','serif';">g. Why is water such a good solvent?

<span style="font-family: 'Times New Roman','serif';">Positive ions attract the negative part of <span style="font-family: 'Times New Roman','serif';">part of water (the atom), <span style="font-family: 'Times New Roman','serif';">while negative ions attract the positive part <span style="font-family: 'Times New Roman','serif';">of water (the ___ atoms).__ __<span style="font-family: 'Times New Roman','serif';">h. Water’s Temperature-Stabilizing Effects: __ __<span style="font-family: 'Times New Roman','serif';">What is temperature? __

__<span style="font-family: 'Times New Roman','serif';">Why is it hard to change the temperature of water? __ __<span style="font-family: 'Times New Roman','serif'; msolist: Ignore;">i. <span style="font-family: 'Times New Roman','serif';">Water’s Cohesion: __ __<span style="font-family: 'Times New Roman','serif';">What is cohesion? __

__<span style="font-family: 'Times New Roman','serif';">How does the cohesion of water molecules help transport water up inside of the tissues of plants? __

__<span style="font-family: 'Times New Roman','serif';">11. Dissolved ions inside of our bodies influence its structure and function. One of the body’s most chemically active ion is the hydrogen ion (H+1). __ __<span style="font-family: 'Times New Roman','serif';"> A. __ are substances that release or donate hydrogen ions (H+1) to a water (aqueous) solution. **Remember that a hydrogen ion is the same thing as a //proton// since it is a hydrogen atom that has lost its electron**//.// <span style="font-family: 'Times New Roman','serif';">1. Strong acids ionize completely releasing their hydrogen ions easily. One example is Hydrochloric acid (HCl) found in the stomach. <span style="font-family: 'Times New Roman','serif';">2. Weak acids may have hydrogen ions to release to solution, but are reluctant or resistant to do so. One example is Carbonic acid (H2CO3) found in soft drinks that is formed when carbon dioxide reacts with water. <span style="font-family: 'Times New Roman','serif';">B. __are substances that accept or bond with hydrogen ions when dissolved in water solutions, thereby removing them or decreasing the number of hydrogen ions remaining in solution. They may also release hydroxide ions (OH-1) to a solution that will then combine with hydrogen ions to form water. These solutions are also known as //alkaline// solutions. This is how //Alka Seltzer// got its name. It reduces the acidity of the stomach when someone has acid indigestion.__ __<span style="font-family: 'Times New Roman','serif';">C. The __ SCALE is used by scientists to represent the nature of a solution relative to the amount of hydrogen ions in solution. The scale extends from a numerical value of __to__. <span style="font-family: 'Times New Roman','serif';">1. Solutions with a value of “0” are very _, meaning there is a high concentration of hydrogen ions in solution. <span style="font-family: 'Times New Roman','serif';"> 2. Solutions with a value of “14” are very (alkaline), <span style="font-family: 'Times New Roman','serif';">meaning there is a very low concentration of hydrogen ions in solution. <span style="font-family: 'Times New Roman','serif';">3. Pure water has a value of “__”, which indicates it is a neutral solution, or in other words one with the same amount of H+1 and OH-1 ions.__ __<span style="font-family: 'Times New Roman','serif';">4. The pH scale is a type of metric scale. This means that for every change in the pH, there is a ten-fold change in the concentration of hydrogen ions. On the metric scale, to change from one unit of measurement to another it is necessary to move the decimal point either to the right or to the left. Each time the decimal point is moved it is equal to multiplying or dividing by 10. If the decimal moves 3 places to the right it is equal to multiplying the value by 10 X 10 X 10 or the final answer is 1,000 times larger. The following are several examples: __ __<span style="font-family: 'Times New Roman','serif';">A solution with a pH = 2 is 10 times more acidic than a solution of pH = 3. __ __<span style="font-family: 'Times New Roman','serif';">A solution with a pH = 5 is 100 times less acidic than a solution of pH = 3. __ __<span style="font-family: 'Times New Roman','serif';"> A solution with a pH = 10 is 100 times more basic than a solution of pH = 8. __ __<span style="font-family: 'Times New Roman','serif';"> A solution with a pH = 6 is 1000 times less basic than a solution of pH = 9. __ __<span style="font-family: 'Times New Roman','serif';">D. _____ are substances that when dissolved in water release ions other than the hydrogen ion (H+1) or hydroxide ion (OH-1). Examples include sodium chloride or table salt (NaCl) and calcium phosphate [ Ca3(PO4)2 ] found in bones. Most salts serve key functions in cells. The ions released into solution in the body are also called “electrolytes”, in that they allow the solution to be able to conduct an electric current.__ __<span style="font-family: 'Times New Roman','serif';">E. ___ are substances that resist a change in pH when an acid or base is added to the solution. They are generally formed by mixing a weak acid and weak base. If a strong acid is added to the mixture, the weak base bonds to the hydrogen ions to neutralize the acid; if a strong base is added to the mixture, the weak acid releases hydrogen ions to neutralize the base. In either case, the pH does not change significantly. <span style="font-family: 'Times New Roman','serif';">Buffers can only work for so long, then the pH will shift rapidly.

<span style="font-family: 'Times New Roman','serif';">12. Give the approximate pH of each of the following solutions then identify each as an acid (A) [pH of 1-6], base (B) [ph of 8-14] or essentially neutral (N) [pH of 6-8].

1. Tomato juice _ __<span style="font-family: 'Times New Roman','serif';">2. Human blood __ _ <span style="font-family: 'Times New Roman','serif';">3. Vinegar _ __<span style="font-family: 'Times New Roman','serif';">4. Pure water __ _ <span style="font-family: 'Times New Roman','serif';">5. Coffee _ __<span style="font-family: 'Times New Roman','serif';">6. Ammonia __ _ <span style="font-family: 'Times New Roman','serif';">7. Seawater _ __<span style="font-family: 'Times New Roman','serif';">8. Typical rainwater __ _ <span style="font-family: 'Times New Roman','serif';">9. Oven / Drain cleaner _ __<span style="font-family: 'Times New Roman','serif';">10. Antacid pills (Tums) __ _ <span style="font-family: 'Times New Roman','serif';">11. Urine _ __<span style="font-family: 'Times New Roman','serif';">12. Gastric juice __ _

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 * <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">13. Complete the following matching **
 * 1. acid stomach || <span style="font-family: 'Times New Roman','serif';">A. || <span style="font-family: 'Times New Roman','serif';">A sometimes irreversible state of unconsciousness ||
 * <span style="font-family: 'Times New Roman','serif';">2. acids || <span style="font-family: 'Times New Roman','serif';">B. || <span style="font-family: 'Times New Roman','serif';">CO2 builds up in the blood, too much H2CO3 forms, and blood pH severely decreases ||
 * <span style="font-family: 'Times New Roman','serif';">3. pH scale || <span style="font-family: 'Times New Roman','serif';">C. || <span style="font-family: 'Times New Roman','serif';">Hydroxide ion ||
 * <span style="font-family: 'Times New Roman','serif';">4. chemical burns || <span style="font-family: 'Times New Roman','serif';">D. || <span style="font-family: 'Times New Roman','serif';">Substances that accept H+ when dissolved in water ||
 * <span style="font-family: 'Times New Roman','serif';">5. H+ || <span style="font-family: 'Times New Roman','serif';">E. || <span style="font-family: 'Times New Roman','serif';">An uncorrected increase in blood pH ||
 * <span style="font-family: 'Times New Roman','serif';">6. bases || <span style="font-family: 'Times New Roman','serif';">F. || <span style="font-family: 'Times New Roman','serif';">Used to measure H+ concentration in various fluids ||
 * <span style="font-family: 'Times New Roman','serif';">7. examples of basic solutions || <span style="font-family: 'Times New Roman','serif';">G. || <span style="font-family: 'Times New Roman','serif';">A partnership between a weak acid and the base that forms when it dissolves in water; counters slight pH shifts ||
 * <span style="font-family: 'Times New Roman','serif';">8. coma || <span style="font-family: 'Times New Roman','serif';">H. || <span style="font-family: 'Times New Roman','serif';">Hydrogen ion or proton ||
 * <span style="font-family: 'Times New Roman','serif';">9. Respiratoryacidosis || <span style="font-family: 'Times New Roman','serif';">I. || <span style="font-family: 'Times New Roman','serif';">Baking soda, seawater, egg white ||
 * <span style="font-family: 'Times New Roman','serif';">10. OH– || <span style="font-family: 'Times New Roman','serif';">J. || <span style="font-family: 'Times New Roman','serif';">Can be caused by ammonia, drain cleaner, and sulfuric acid in car batteries ||
 * <span style="font-family: 'Times New Roman','serif';">11. tetany || <span style="font-family: 'Times New Roman','serif';">K. || <span style="font-family: 'Times New Roman','serif';">Substances that donate H+ when dissolved in water ||
 * <span style="font-family: 'Times New Roman','serif';">12. examples of acid solutions || <span style="font-family: 'Times New Roman','serif';">L. || <span style="font-family: 'Times New Roman','serif';">Lemon juice, gastric fluid, coffee ||
 * <span style="font-family: 'Times New Roman','serif';">13. alkolosis || <span style="font-family: 'Times New Roman','serif';">M. || <span style="font-family: 'Times New Roman','serif';">A potentially lethal pH stage in which the body’s skeletal muscles enter a state of uncontrollable contraction ||
 * <span style="font-family: 'Times New Roman','serif';">14. buffer system || <span style="font-family: 'Times New Roman','serif';">N. || <span style="font-family: 'Times New Roman','serif';">Can be caused by eating too much fried chicken or certain other foods ||

<span style="font-family: 'Times New Roman','serif';">Chapter review: Answer the following essay questions.

<span style="font-family: 'Times New Roman','serif';">14. a. If a sulfur atom has six electrons in its outer shell of electrons, how many covalent bonds is it likely to form with other atoms? Why?

<span style="font-family: 'Times New Roman','serif';">b. If a hydrogen atom has one electron in its outer shellof electrons, how many covalent bonds is it likely to form with other atoms? Why?

<span style="font-family: 'Times New Roman','serif';">c. What do you think the chemical formula for hydrogen sulfide would be? <span style="font-family: 'Times New Roman','serif';"> Hint: Look at the location of sulfur compared to oxygen on the periodic table.

<span style="font-family: 'Times New Roman','serif';">15. In your own words, explain the main difference between a polar covalent bond and a nonpolar covalent bond.

<span style="font-family: 'Times New Roman','serif';">16. If a water molecule is neutral (has no net charge), then why does it attract polar molecules and repel nonpolar ones.

<span style="font-family: 'Times New Roman','serif';">17. Explain why sweating helps cool the body when it is overheated?

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">1. A substance that cannot be broken down into simpler substances by ordinary <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">chemical means is known as a(n) <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. molecule <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. ion <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. element <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. compound <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. isotope
 * //<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Sample Test Questions for chapter 2 and Lab #6: //**

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">2. A sulfur atom has 6 electrons in its outer energy shell. As a result, it tends to form <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;"> __covalent bonds with other atoms.__ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. 2 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. 3 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. 4 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. 6 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. 8 __

__<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">3. A phosphorus atom has an atomic mass (mass number) of 31 and an atomic number __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">of 15. How many PROTONS are there in a neutral phosphorus atom? __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. 15 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. 16 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. 31 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. 46 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. none of the above __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">4. A __ __is a subatomic particle that carries a__ __charge.__ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. proton……negative __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. electron…..negative __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. neutron…..negative __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. proton…..neutral __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. electron……neutral __

__<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">5. Isotopes of an element differ in their number of: __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. electrons __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. bonds formed by the atom __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. protons __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. neutrons __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. nuclei __

__<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">6. When hydrogen atoms lose one electon to become an ion, their net electrical charge is __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. +1 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. -1 __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. remains neutral __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. impossible to know from just this information provided __ __<span style="font-family: 'Times New Roman','serif'; font-size: 10pt;">BIOL 160: Module 1 - 28 - __

__<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">7. A solution at pH of 4 contains __ the concentration of Hydrogen ions <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">as the same amount of a solution with a pH of 2. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. 2 times more <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. 2 times less <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. 20 times more <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. 20 times less <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. 100 times less

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">8. This property of water makes it possible for columns of liquid water to rise from roots to leaves inside narrow pipelines of vascular tissues inside a plant. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. cohesion <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. temperature <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. water sickness <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. surface tension <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. none of the above

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">9. Bonds that form when atoms transfer one or more electrons are called __bonds.__ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. ionic __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. polar covalent __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. hydrogen __ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. non-polar covalent __

__<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">10. Within water molecules, the hydrogen atoms are bonded to the oxygen atom by __ __bonds, whereas the hydrogen atoms form__ ___ bonds with <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">neighboring water molecules. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. hydrogen…..ionic <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. ionic……hydrogen <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. polar covalent…….ionic <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. polar covalent……hydrogen <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. hydrogen…….polar covalent

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">11. A //solvent// is <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. the dissolving agent of a solution <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. generally the liquid portion of a solution <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. usually water in living organisms <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. generally the portion of a solution found in smaller amount <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">e. A, B and C are all correct

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">12. If a sample has a mass of 0.08 grams, what is this mass measured in milligrams? <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">a. 0.00008 <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">b. 0.008 <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">c. 0.08 <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">d. 8.0 <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">e. 80