A number placed in front of a chemical symbol or formula showing how many molecules of the substance are involved in the reaction.

a.Valence electrons
b.Ion
c.Law of Conservation of Matter
d.Chemical bonds
e.Reactants
f.Electronegativity
g.Chemical reaction
h.Balanced chemical equation
i.Groups
j.Products
k.Coefficient
l.Periods
m.Chemical formula
n.Polyatomic ion