Chemistry Chapter 2 Vocab

Front 1

law of definite proportions

Back 1

different samples of the same compound always contain its constituent elements in the same proportion by mass

Front 2

law of multiple proportions

Back 2

if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in ratios of small whole numbers

Front 3

law of conservation of mass

Back 3

matter can be neither created nor destroyed

Front 4

atom

Back 4

the basic unit of an element that can enter into chemical combination

Front 5

radiation

Back 5

the emission and transmission of energy through space in the form of waves

Front 6

electrons

Back 6

negatively charged particles

Front 7

radioactivity

Back 7

spontaneous emission of particles and/or radiation

Front 8

alpha rays

Back 8

consist of positively charged particles called alpha particles and therefore are deflected by the positively charged plate

Front 9

beta rays

Back 9

emitted electrons that are deflected by the negatively charged plate

Front 10

gamma rays

Back 10

high energy rays with no charge that are not affected by an external field

Front 11

nucleus

Back 11

dense central core within the atom

Front 12

proton

Back 12

the positively charged particles in the nucleus

Front 13

neutrons

Back 13

electrically neutral particles having a mass slightly greater than that of protons

Front 14

atomic number

Back 14

the number of protons in the nucleus of each atom of an element

Front 15

mass number

Back 15

the total number of neutrons and protons present in the nucleus of an atom of an element

Front 16

isotopes

Back 16

atoms that have the same atomic number but different mass numbers

Front 17

periodic table

Back 17

a chart in which elements having similar chemical and physical properties are grouped together

Front 18

periods

Back 18

horizontal rows in the periodic table

Front 19

groups or families

Back 19

vertical columns in the periodic table

Front 20

metal

Back 20

good conductor of heat and electricity

Front 21

nonmetal

Back 21

a poor conductor of heat and electricity

Front 22

metalloid

Back 22

has properties that are intermediate between those of metals and nonmetals

Front 23

alkali metals

Back 23

the group 1A elements (Li, Na, K, Rb, Cs, and Fr)

Front 24

alkaline earth metals

Back 24

the group 2A elements (Be, Mg, Ca, Sr, Ba, and Ra)

Front 25

halogens

Back 25

the group 7A elements (F, Cl, Br, I, and At)

Front 26

noble gases

Back 26

elements in group 8A (He, Ne, Ar, Kr, Xe, Rn)

Front 27

molecule

Back 27

an aggregate of at least two atoms in a definite arrangement held together by chemical forces, or chemical bonds

Front 28

diatomic molecule

Back 28

molecule containing only two atoms

Front 29

polyatomic molecules

Back 29

molecules containing more than two atoms

Front 30

ion

Back 30

an atom or group of atoms that has a net positive or negative charge

Front 31

cation

Back 31

an ion with a net positive charge

Front 32

anion

Back 32

an ion whose net charge is negative

Front 33

ionic compound

Back 33

compound formed from cations and anions

Front 34

monatomic ions

Back 34

ions that contain only one atom

Front 35

polyatomic ions

Back 35

ions containing more than one atom

Front 36

chemical formulas

Back 36

express the composition of molecules and ionic compounds in terms of chemical symbols

Front 37

molecular formula

Back 37

shows the exact number of atoms of each element in the smallest unit of a substance

Front 38

allotrope

Back 38

one of two or more distinct forms of an element

Front 39

structural formula

Back 39

shows how atoms are bonded to one another in a molecule

Front 40

empirical formula

Back 40

tells us which elements are present and the simplest whole-number ratio of their atoms, but not necessarily the actual number of atoms in a given molecule

Front 41

organic compounds

Back 41

compounds that contain carbon, usually in combination with elements such as hydrogen, oxygen, nitrogen, and sulfur

Front 42

inorganic compounds

Back 42

all compounds that do not contain carbon

Front 43

binary compounds

Back 43

compounds formed from just two elements

Front 44

ternary compounds

Back 44

compounds consisting of three elements

Front 45

acid

Back 45

substance that yields hydrogen ions when dissolved in water

Front 46

oxoacids

Back 46

acids that contain hydrogen, oxygen, and another element (the central element)

Front 47

oxoanions

Back 47

anions of oxoacids

Front 48

base

Back 48

substance that yields hydroxide ions when dissolved in water

Front 49

hydrates

Back 49

compounds that have a specific number of water molecules attached to them