Chem Review terms

Question 1

anything that takes up space and has mass

Answer 1

Matter

Question 2

is a pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means

Answer 2

Element

Question 3

is a substance composed of two or more elements joined by chemical bonds.

Answer 3

Compound

Question 4

smallest quantity of an element that retains the unique properties of that element
“are the smallest stable units of matter”

Answer 4

Atom

Question 5

Atoms are composed of _____ that determine the structure of an object

Answer 5

subatomic particles

Question 6

the number of protons in the nucleus of the atom, identifies the element.

Answer 6

Atomic Number

Question 7

is the sum of the number of protons and neutrons in its nucleus

Answer 7

mass number

Question 8

is one of the different forms of an element, distinguished from one another by different numbers of neutrons. (elements whose atoms nuclei contain the same number of protons but a different number of neutrons)

Answer 8

isotrope

Question 9

•an isotope whose nucleus readily decays, giving off subatomic particles and electromagnetic energy

Answer 9

radioactive isotope

Question 10

is a layer of electrons that encircle the nucleus at a distinct energy level.

Answer 10

electron shell

Question 11

•is an atom’s outermost electron shell

Answer 11

valence shell

Question 12

•All atoms (except hydrogen and helium with their single electron shells) are most stable when there are exactly eight

Answer 12

octet rule

Question 13

the average of the mass of all its isotopes

Answer 13

Atomic mass (or weight

Question 14

(= electron shell model) – depicts electrons in circular orbitals or shells around the nucleus

Answer 14

Planetary model

Question 15

(= electron cloud model) – depicts “probable” regions of greatest electron density by shading

Answer 15

Orbital model

Question 16

a weak or strong electrical attraction that holds atoms in the same vicinity

Answer 16

bond

Question 17

A more or less stable grouping of two or more atoms held together by chemical bonds

Answer 17

molecule

Question 18

When a molecule is made up of two or more atoms of different elements

Answer 18

chemical compound

Question 19

An atom that has an electrical charge—whether positive or negative

Answer 19

ion

Question 20

A positively charged ion

Answer 20

cation

Question 21

A negatively charged ion

Answer 21

anion

Question 22

an ongoing, close association between ions of opposite charge

Answer 22

ionic bond

Question 23

meaning chemically unreactive element due to already having a full valence shell

Answer 23

inert

Question 24

molecules share electrons in a mutually stabilizing relationship.

Answer 24

covalent bond

Question 25

e-’s shared equally between atoms in covalent bond

Answer 25

Nonpolar Covalent Bonds

Question 26

e-’s not shared equally between atoms in covalent bond

Answer 26

Polar Covalent Bonds

Question 27

is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for
example, the oxygen in the water molecule) is attracted to another electronegative atom from another molecule

Answer 27

hydrogen bond

Question 28

is the form of energy powering any type of matter in motion

Answer 28

kinetic energy

Question 29

the form of potential energy in which energy is stored in chemical bonds

Answer 29

chemical energy

Question 30

is the energy of position, or the energy matter possesses because of the positioning or structure of its components.

Answer 30

potential energy

Question 31

Chemical reactions that release more energy than they absorb are

Answer 31

exergonic

Question 32

chemical reactions that absorb more energy than they release are

Answer 32

endergonic

Question 33

is energy stored in physical systems such as machines, engines, or the human body, directly powers the movement of matter.

Answer 33

mechanical energy

Question 34

is energy emitted and transmitted as waves rather than matter

Answer 34

radiant energy

Question 35

supplied by electrolytes in cells and body fluids, contributes to the voltage changes that help transmit impulses in nerve and muscle cells

Answer 35

electrical energy

Question 36

one or more substances that enter into the reaction.

Answer 36

reactant

Question 37

one or more substances produced by a chemical reaction

Answer 37

product

Question 38

is a chemical reaction that results in the joining of components that were formerly separate

Answer 38

synthesis reaction

Question 39

is a chemical reaction that breaks down something larger into its constituent parts

Answer 39

decomposition reaction

Question 40

is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both
formed and broken, and chemical energy is absorbed, stored, and released

Answer 40

exchange reaction

Question 41

the capacity to do work

Answer 41

energy

Question 42

is a substance that increases the rate of a chemical reaction without itself undergoing any change

Answer 42

catalyst

Question 43

is a catalyst composed of protein or ribonucleic

acid (RNA)

Answer 43

enzyme

Question 44

the “threshold” level of

energy needed to break the bonds in the reactants

Answer 44

activation energy

Question 45

decomposition reactions which produce ATP from food molecules
- are also a type of exchange reaction as electrons are transferred between atoms and molecules

Answer 45

Oxidation-reduction reactions