Maren

Front 1

chemistry

Back 1

the study of the composition, structure, and properties of matter and the changes it undergoes

Front 2

atom

Back 2

smallest unit of an element that maintains the properties of that element

Front 3

mass

Back 3

a measure of the amount of matter

Front 4

element

Back 4

a pure substance made of only one kind of atom

Front 5

compound

Back 5

a substance that is made from the atoms of two or more elements that are chemically bonded in a definite ratio

Front 6

a system

Back 6

what is under study; not the surroundings

Front 7

hypothesis

Back 7

scientific guess

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model

Back 8

a representation of something that can't easily be viewed directly

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theory

Back 9

an explanation of observed phenomena which has been tested and verified

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a quantity

Back 10

something that has magnitude, size, or amount

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the law of conservation of mass

Back 11

mass is neither created nor destroyed during ordinary chemical or physical reactions

Front 12

the law of definite proportions

Back 12

a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound

Front 13

the law of multiple proportions

Back 13

if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

Front 14

atomic number

Back 14

the number of protons in the nucleus of each atom of that nucleus

Front 15

isotopes

Back 15

atoms of the same element that have different masses

Front 16

mass number

Back 16

the total number of protons and neutrons in the nucleus of an isotope

Front 17

nuclide

Back 17

a general term for any isotope of any element

Front 18

atomic mass unit

Back 18

exactly 1/12 the mass of a carbon-12 atom

Front 19

average atomic mass

Back 19

the weighted average of the atomic masses of the naturally occurring isotopes of an element

Front 20

mole

Back 20

the amount of a substance that contains as many particles as there are in exactly 12 grams of carbon-12

Front 21

electromagnetic radiation

Back 21

a form of energy that exhibits wavelike behavior as it travels through space

Front 22

wavelength

Back 22

the distance between corresponding points on adjacent waves

Front 23

frequency

Back 23

the number of waves that pass a given oint in a specific time, usually one second

Front 24

the photoelectric effect

Back 24

the emission of electrons from a metal when light shines on the metal

Front 25

a quantum

Back 25

the minimum quantity of energy that can be lost or gained by an atom

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a photon

Back 26

a particle of electromagnetic radiation having zero rest mass and carrying a quantum of energy

Front 27

the quantum theory of the atom

Back 27

it describes mathematically the wave properties of electrons and other very small particles

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heisenberg uncertainty principle

Back 28

it is impossible to determine simultaneously both the position and velocity of an electron or any other particle

Front 29

an orbital

Back 29

a three-dimensional region around the nucleus that indicates the probably location of an atom

Front 30

quantum numbers

Back 30

specify the properties of atomic orbitals and the properties of electrons in orbitals

Front 31

an electron configuration

Back 31

the arrangement of electrons in an atom

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the aufbau principle

Back 32

an electron occupies the lowest-energy orbital that can receive it

Front 33

the pauli exclusion principle

Back 33

no two electrons in the same atom can have the same set of four quantum numbers

Front 34

hund's rule

Back 34

orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin

Front 35

periodic law

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the physical and chemical properties of the elements are periodic functions of their atomic numbers

Front 36

the periodic table

Back 36

an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column or group

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atomic radius

Back 37

1/2 of the distance between the nuclei of identical atoms that are bonded together

Front 38

ionization energy

Back 38

the energy required to remove one electron from a neutral atom of an element

Front 39

electronegativity

Back 39

a measure of the ability of an atom in a chemical compound to attract electrons

Front 40

cation

Back 40

a positive ion

Front 41

anion

Back 41

a negative ion

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a chemical bond

Back 42

a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together

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nonpolar covalent bond

Back 43

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

Front 44

polar covalent bond

Back 44

a covalent bond in which the bonded atoms have an unequal attraction for the shared electrons

Front 45

molecule

Back 45

a neutral group of atoms that are held together by covalent bonds

Front 46

chemical formula

Back 46

indicates the relative numbers of atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts

Front 47

molecular formula

Back 47

shows the types and numbers of atoms combined in a single molecule of a molecular compound

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diatomic molecule

Back 48

a molecule containing only two atoms

Front 49

the octet rule

Back 49

chemical compounds tend to form so that each atom, by gining, losing, or sharing electrons, has an octet of electrons in its highest occupied energy level

Front 50

structural formula

Back 50

indicates the kind, number, arrangement, and bonds but not the unshared pairs of the atoms in a molecule

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single covalent bond

Back 51

a covalent bond prodced by the sharing of one pair of electrons between two atoms

Front 52

double covalent bond

Back 52

a covalent bond produced by the sharing of two pairs of electrons between two atoms

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triple covalent bond

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a covalent bond produced by the sharing of three pairs of electrons between two atoms

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ionic compound

Back 54

composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal

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a formula unit

Back 55

the simples collection of atoms from which an ionic compounds formula can be established

Front 56

polyatomic ion

Back 56

a charged group of covalently bonded atoms

Front 57

metallic bonding

Back 57

the chemical bonding that results from the attraction betwen metal atoms and the surrounding sea of electrons

Front 58

VSEPR theory

Back 58

repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far apart as possible