Electron Dot Diagram Symbol for an element with dots surrounding it. The dots stand for

the valence electrons.

Chemical Bond

Force of attraction that holds two atoms together

Ion

An atom or a group of atoms that has an electric charge

Polyatomic IonsIons that are made of more

than one atom

Ionic BondAttraction between two oppositely charged ions

Ionic CompoundCompound that has

positive and negative ions

Chemical FormulaCombination of symbols that show the ratio of elements in

a compound

Subscript

Ratio of elements in a compound

Crystal

Ions that form a three dimensional arrangement

Covalent Bond

Chemical bond when two atoms share electrons

Molecule

Neutral group of atoms joined by covalent bonds

Double BondWhen two atoms share two

pairs of electrons

Triple Bond

When atoms share three pairs of electrons

Polar Bond

When electrons are shared unequally

Nonpolar Bond

A bond where electrons are shared equally

Valence Electrons

Electrons that have the highest energy level and are held loosely

Diatomic Molecule Molecule that consists of two

atoms

Chemical ChangesForm new substances when bonds break and new bonds

form

PrecipitateWhen a solid forms from a

liquid.

Endothermic reactionHeat energy is transferred into chemical bonds (matter gets

colder)

Exothermic ReactionWhen the breaking and remaking of

bonds releases energy (nearby matter gets hotter)

Chemical EquationUsing chemical symbols, + and to

summarize a chem. reaction

CatalystSubstance that speeds up a chemical reaction without being destroyed in

the reaction.

Exothermic ReactionWhen the breaking and remaking of

bonds releases energy (nearby matter gets hotter)