Chapter 2 - Chemical Basis of Life

Question 1

Matter

Answer 1

Anything that contains mass and occupies space
Matter may exist as solid, liquid or gas.
Composed of atoms

Question 2

Atoms

Answer 2

Smallest functional units of matter - can’t be broken down by ordinary chem or physical means

Question 3

Molecules

Answer 3

two or more atoms bonded together

Question 4

Element

Answer 4

Pure substance made up of only one kind of atom (oxygen, hydrogen, etc)

Question 5

Atomic nucleus

Answer 5

where you go to get the protons and neutrons, while the electrons hang outside

Question 6

orbital

Answer 6

region in an atom where there is a high probability of finding an electron
some are spherical, called S orbitals. Some look more like a properller or dumbell, called P orbital
An orbital contains a maximum of 2 electrons - any orbital with more than 2 electrons must contain more than one orbital

Question 7

electron shells

Answer 7

contain orbitals
An electron shell is a region outside the nucleus of an atom occupied by electrons of a given energy level. More than one orbital can be found within an electron shell. An orbital may be spherical or dumbbell-shaped and contains up to two electrons.

Question 8

Energy

Answer 8

capacity to do work or cause a change

Question 9

atomic number

Answer 9

number of protons in an atom. Unique to that atom (also equal to electrons, except for ions)

Question 10

Atomic Mass

Answer 10

atomic mass indicates an atom’s mass relative to the masses of other atoms

Question 11

mole

Answer 11

same number of particles as there are atoms in 12 grams of carbon.
12 grams of carbon = 1 mole of carbon

Question 12

isotopes

Answer 12

elements that differ in the number of neutrons; example c12 vs c14
they have similar chemical properties but different physical properties
many are inherently unstable

Question 13

half life

Answer 13

time it taes for 50% of an isotopye to decay

Question 14

radioisotope

Answer 14

unstable; emit radiation which converts them to a stable form

Question 15

molecule

Answer 15

two or more atoms bonded

Question 16

compound

Answer 16

two or more elements of different types linked together: example, water (H2o)
they contain emergent properties (different than individual characteristics)
held together by chemical bonds

Question 17

covalent bond

Answer 17

molecule where two atoms share a pair of electrons; can occur with atoms where outer shells are not full
- they tend to be most stable when outer shells are full
-strong bonds
covalent bond sharing looks like this: h20 = H-O-H
sometimes a double bond occurs - atoms share more than one pair of electrons; example O2

Question 18

octet rule

Answer 18

most atoms are stable when they have 8 electrons in their outer shell
applies to most atoms in living things
doesn’t always apply (example hydrogen)

Question 19

polar covalent bonds

Answer 19

atoms who have an electromagnetic charge; these attract electrons closer when shared with non-electromagnet atoms
water is a great example; oxygen is more electronegative than hydrogen, so the electrons pull closer to it and it gives the region a negative charge. Hydrogen is positively charged.

Question 20

nonpolar covalent

Answer 20

bonds between atoms with similar electronegativities (carbon to carbon, as an example)

Question 21

ion

Answer 21

an atom that gains or loses an electron and consequently has a charge (example: sodium)

Question 22

cations

Answer 22

ions with a net positive charge

Question 23

anions

Answer 23

an ion with a net negative charge

Question 24

free radical

Answer 24

molecule with an unpaired electron in its outer shell
example: nitric oxide
free radicals can be charged or neutral
vitamins donate electrons to free radicals without becoming massively charged themselves