2.3.2—Balanced and ionic equations

A balanced chemical equation conserves each element: the number of atoms of every element is the same on both sides. For an ionic equation, total charge must also be conserved, and state symbols should identify the reacting species and products.

Use a fixed sequence: (1) write the correct formulae and state symbols, (2) count atoms on both sides, (3) change coefficients until every element balances, (4) simplify to the smallest whole-number ratio, and (5) check atoms, charge and states. Never change a formula subscript to balance an equation.

To obtain a net ionic equation, write the complete ionic equation, split only appropriate aqueous strong electrolytes into ions, then cancel ions that are unchanged on both sides. The remaining species are the particles that undergo the chemical change; recheck charge as well as atom counts.

Coefficients change the amounts of substances while subscripts define the substances themselves. Do not cancel a reacting ion as a spectator, assume every dissolved species should be split, or omit state symbols when they are needed to distinguish the ionic form.