Atomic Structure. State Symbols used in Chemical Equations.. The equations from the two previous pages 2K + Cl 2 2KCl 4Li + O 2 2Li 2 O still require state symbols to be complete.. The complete equations in words and symbols would be potassium + chlorine potassium chloride. 2K (s) + Cl 2 (g) 2KCl (s). lithium + oxygen lithium oxide.