Page 329 - Theory and Problems of BEGINNING CHEMISTRY

318 GLOSSARY

half-life the time it takes for one-half of the nuclei of any given sample of a particular radioactive isotope to
disintegrate spontaneously.
half-reaction the oxidation or reduction half of a redox reaction.
halogen an element of periodic group VIIA: F, Cl, Br, I (or At).
heat a form of energy; the only form of energy that cannot be completely converted into another form.

heat capacity the energy required to change a certain quantity of a substance by a certain temperature.
heavy hydrogen deuterium.
Heisenberg uncertainty principle the location and the energy of a small particle such as an electron cannot
both be known precisely at any given time.
heterogeneous having distinguishable parts.
homogeneous alike throughout; having parts that are indistinguishable even with an optical microscope.
Hund’s rule of maximum multiplicity when electrons partially fill a subshell, they remain as unpaired as
possible.
hydrate a compound composed of a stable salt plus some number of molecules of water, for example,
CuSO 4 ·5H 2 O.
hydrocarbon a compound of carbon and hydrogen only.
+
hydronium ion H 3 O ; the combination of a proton and water.
hypo prefix meaning “still fewer oxygen atoms.”

hypothesis a proposed explanation of observable results.

ideal gas law PV = nRT.
indicator a substance that has an intense color that changes depending on the acidity of a solution. Indicators
are used to determine when the endpoint of a titration has been reached.

initial concentration the concentration in an equilibrium system before the equilibrium reaction has proceeded
at all.
inner transition series the two series of elements at the bottom of the periodic table. The series containing
elements 58 to 71 and 90 to 103, arising from the filling of 4f and 5f subshells.
interpolation reading a graph between the experimental points.
inverse proportion as the value of one variable rises, the value of the other goes down by the same factor.
Inversely proportional variables have a constant product, for example, PV = k for a given sample of gas at
constant temperature.
ion a charged atom or group of atoms.

ion-electron method a method of balancing redox equations using ions in half-reactions.
ionic bond the attraction between oppositely charged ions.
ionization constant the equilibrium constant for the reaction of a weak acid or base with water.

isomerism existence of isomers.
isomers different compounds having the same molecular formula.
isotopes two or more atoms of the same element with different numbers of neutrons in their nuclei.

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joule a unit of energy. 4.184 J raises the temperature of 1.00 g of water 1.00 C.