octet rule
atoms tend to achieve the electron configuration of a noble gas; typically they strive to have 8 electrons in their outer shell
noble-gas configuration
another name for octet rule where atoms strive to have a full outer shell
valence electron
electrons in the outermost energy level of an atom
halide ion
Name for the type of ions formed by Group 7/17 elements (the halogens)
ionic bond
attractive force holding oppositely charged ions (cations and anions) together
electron dot structure
notation depicting valence electrons as dots around an element's atomic symbol (p. 195)
metallic bond
attractive force holding metals together that consists of an attraction of free-floating valence electrons to metal cations (p. 209)
covalent bond
bond formed by the sharing of electrons between atoms (p. 215)
polar bond
molecule in which one side is slightly negative and the opposite side is slightly positive due to unequal sharing of electrons
nonpolar bond
covalent bond in which electrons are shared equally by two atoms
structural formula
chemical formula showing arrangement of atoms in a molecule or polyatomic ion
single covalent bond
bond that forms when two atoms share a pair (2) electrons (p. 226)
double covalent bond
bond that forms when two atoms share two pairs (4) electrons
triple covalent bond
bond that forms when two atoms share three pairs (6) electrons
alkali metals
Family of metals found in Group 1 that have 1 electron in their outer shell and are the most reactive family of the periodic table
alkaline earth metals
Family of metals found in Group 2 that have 2 electrons in their outer shell
halogens
Family of nonmetals found in Group 7/17 that form 'salts' and have 7 electrons in their outer shell
noble gases
Family of nonmetals found in Group 8/18 that have complete outer shells and are typically unreactive. Most other elements strive to reach the same electron configuration as noble gases
inner transition metals
Family of metals that are found below the main body of the periodic table and are composed of the actinide and lanthanide series
ion
atom or group of atoms that has gained or lost electrons and has a charge (negative or positive) as a result
cation
an ion with a positive charge
anion
an ion with a negative charge
chemical formula
an expression indicating the number and types of atoms present in the smallest ratio of the substance (ex. NaCl) (p. 202)
polyatomic ion
tightly bound group of atoms behaving as a unit that has a positive or negative charge (ex. ammonium) (p. 232)
alloy
mixtures of two or more elements which properties superior to their individual elements
molecule
neutral group of atoms joined together by covalent bonds
diatomic molecule
molecule containing only two atoms of the same element (ex. O2) (p. 223)
binary compound
compound that is composed of only two elements (p. 272)
molecular formula
chemical formula that shows the total number of atoms of each element in a substance
lone pair
pair of valence electrons not shared between atoms (p. 227)
bond dissociation energy
energy needs to break a bond between two covalently bonded atoms (p. 236); single bonds are the weakest and triple bonds are the strongest
resonance structure
structures used to envision the bonding in molecules that cannot be adequately described by a single structural formula; they are hybrids of all the single individual structures
bonding orbital
orbital overlap that results in a covalent bond
sigma bond
combining of two atomic orbitals in a direct overlap; all bonds (single, double, and triple) have one sigma bond
pi bond
partial overlap of two atomic orbitals; a double bond has one pi bond, while a triple bond has two pi bonds
VSEPR theory
repulsion between electron pairs causes molecular shapes to adjust so that the electron pairs stay as far apart as possible; tells only about the shape of a molecule (p. 242)
hybridization theory
the hybridization, or fusing, of many atomic orbitals to form equivalent hybrid orbitals; theory is used to tell the molecular shape and type of bonds formed (p. 244)
dipole
molecule with two opposite poles; one that is slightly negative and the other that is slightly positive
van der Waals forces
name for the two weakest intermolecular forces keeping molecules attracted to each other in a substance (p. 250)
dipole interactions
type of van der Waal force where polar molecules are attracted to each other due to their slight positive/negative poles
dispersion forces
weakest of all molecular interactions caused by the motion of electrons resulting in temporarily induced dipoles
hydrogen bonds
strongest of all intermolecular forces in which a hydrogen covalently bonded to an electronegative atom is weakly bonded to an unshared electron pair of another electronegative atom; occurs between N-H, F-H, and O-H bonds (p. 251)
mole
S.I. unit of measurement of the amount of a substance; contains 6.02 x 10�� particles of whatever is being measured
Avogadro's number
6.02 x 10��, the number of particles in a mole (p. 308)
molar mass
the mass of a mole of any substance, in grams (p. 313)
standard temperature and pressure (STP)
a standard measure of temperature and pressure used to compare gases; 0�C and 101.3 kPa (1 atm)
percent composition
percent by mass of each element in a compound (p. 325)
empirical formula
the lowest whole-number ratio of the atoms or moles of the elements in a compound (p. 330)