Chapter 2

Question 1

Anion

Answer 1

A negatively charged ion

Question 2

Atom

Answer 2

The smallest unit of matter that retains the properties of an element

Question 3

Atomic Mass

Answer 3

The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom

Question 4

Atomic Nucleus

Answer 4

An atom’s dense central core, containing protons and neutrons

Question 5

Atomic Number

Answer 5

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript

Question 6

Cation

Answer 6

A positively charged ion

Question 7

Chemical Bond

Answer 7

An attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shell

Question 8

Compound

Answer 8

A substance consisting of two or more different elements combined in a fixed ratio

Question 9

Dalton

Answer 9

A measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or AMU

Question 10

Double Bond

Answer 10

A double covalent bond; the sharing of two pairs of valence electrons by two atoms

Question 11

Electron

Answer 11

A subatomic particle with a single negative electrical charge and a mass about 1/2,000 that of a neutron or proton. One or more electrons move around the nucleus of an atom

Question 12

Electronegativity

Answer 12

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

Question 13

Electron Shell

Answer 13

An energy level of electrons at a characteristic average distance from the nucleus of an atom

Question 14

Element

Answer 14

Any substance that cannot be broken down to any other substance by chemical reactions.

Question 15

Energy

Answer 15

the capacity to cause change, especially to do work (to move matter against an opposing force)

Question 16

Essential Element

Answer 16

A chemical element required for an organism to survive, grow, and reproduce

Question 17

Half-life

Answer 17

The amount of time it takes for 50% of a sample of a radioactive isotope to decay

Question 18

Hydrogen Bond

Answer 18

A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule

Question 19

Ionic Bond

Answer 19

A chemical bond resulting from the attraction between oppositely charged ions

Question 20

Ionic Compound

Answer 20

A compound resulting from the formation of an ionic bond; also called a salt

Question 21

Ion

Answer 21

An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge

Question 22

Isotope

Answer 22

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass

Question 23

Mass Number

Answer 23

The sum of the number of protons and neutrons in an atom’s nucleus

Question 24

Matter

Answer 24

Anything that takes up space and has mass

Question 25

Molecule

Answer 25

Two or more atoms held together by covalent bonds

Question 26

Neutron

Answer 26

A subatomic particle having no electrical charge (electrically neutral) found in the nucleus of an atom

Question 27

Nonpolar Covalent Bond

Answer 27

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity

Question 28

Orbital

Answer 28

The three-dimensional space where an electron is found 90% of the time

Question 29

Polar Covalent Bond

Answer 29

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive

Question 30

Potential Energy

Answer 30

The energy that matter possesses as a result of its location or spatial arrangement

Question 31

Product

Answer 31

A material resulting from a chemical reaction

Question 32

Proton

Answer 32

A subatomic particle with a single positive electrical charge, found in the nucleus of an atom

Question 33

Radioactive Isotope

Answer 33

An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy.

Question 34

Radiometric Dating

Answer 34

A method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes

Question 35

Reactant

Answer 35

A starting material in a chemical reaction

Question 36

Salt

Answer 36

A compound resulting from the formation of an ionic bond; also called an ionic compound

Question 37

Single Bond

Answer 37

A single covalent bond; the sharing of a pair of valence electrons by two atoms

Question 38

Trace Element

Answer 38

An element indispensable for life but required in extremely minute amounts

Question 39

Valence

Answer 39

The bonding capacity of a given atom; usually equals the number of unpaired electrons required to complete the atom's outermost (valence) shell

Question 40

Valence Electron

Answer 40

An electron in the outermost electron shell

Question 41

Valence Shell

Answer 41

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom

Question 42

van der Waals interactions

Answer 42

Weak attractions between molecules or parts of molecules that result from the transient local partial charges