Biology Ch.2

Question 1

Electron shells

Answer 1

first shell (2 electrons), second and third max 8 electrons

Question 2

Valence electrons

Answer 2

outer shell electron –> interacts with other atoms

Question 3

If the valence orbital is full

Answer 3

the atom is inert, meaning unlikely to react

Question 4

3 types of chemical bonds

Answer 4

covalent bonds
ionic bonds
hydrogen bonds

Question 5

covalent bonds

Answer 5

share valence electrons, the valence shells overlap, each electron completing the valence shell for the other

Question 6

polar covalent bond

Answer 6

electronegetivities in a compound are unequal –> resulting in a partial differences on different sides of the moelcule

Question 7

Nonpolar covalent bond

Answer 7

the electronegativities of the atoms are equal

Question 8

electronegativitty

Answer 8

the attraction of a given atom for the electrons of a covalent bond

Question 9

Ionic bonds

Answer 9

former by electrical attractions between opposite charges and ions

Question 10

anion

Answer 10

negatively charged (gain e)

Question 11

cation

Answer 11

positively charged (loses e)

Question 12

Hydrogen bond

Answer 12

non-covalent (does not share electrons) between hydrogen and an electronegative atom

Question 13

bond strength order

Answer 13

covalent (strongest), followed by ionic, then hydrogens

Question 14

what can affect molecule shape

Answer 14

electronegativities and bonds

Question 15

cohesion

Answer 15

water molecules stick together (many hydrogen bonds, responsible for surface tension)

Question 16

adhesion

Answer 16

hydrogen bonds between water molecules and other molecules

Question 17

thermal energy

Answer 17

kinetic energy associated with random movements of atoms and molecules to change temp 1C

Question 18

specific heat

Answer 18

amount of heat that must be absorbed or lost

Question 19

whats special about water and its absorption/loss of energy

Answer 19

water has a very high specific heat meaning it takes a lot of energy to change the temp of water, but it manages to then hang onto that energy. also takes a lot of energy for water to evaporate –> sweat!

Question 20

Solution

Answer 20

liquid homogenous mixture of two or more substances

Question 21

solvent

Answer 21

substance that solute dissolves in

Question 22

solute

Answer 22

substance that dissolves

Question 23

water is…

Answer 23

a good solvent! it dissolves polar substances

Question 24

hydrophilic

Answer 24

water loving, polar substances dissolve easily

Question 25

Hydrophobic

Answer 25

water hating, things that do not dissolve in water = non-polar molecules

Question 26

Acid

Answer 26

substance that increases H+ concentration

Question 27

Base

Answer 27

substance that releases OH-, REDUCES H+ concentration

Question 28

as pH number gets smaller, the number of hydrogens…

Answer 28

increases

Question 29

subatomic particles

Answer 29

protones, neutrons, electrons

Question 30

atomic number

Answer 30

of protons

Question 31

mass number

Answer 31

of protons + # of neutrons

Question 32

Isotopes

Answer 32

same element, different number of neutrons

Question 33

buffers

Answer 33

substances that minimize changes in concentration of H+ and OH- in a solution by donating or accepting H+