The balanced equation for the reaction of magnesium bromide and chlorine is MgBr2 + Cl2 = Br2 + MgCl2. MgBr2 is the formula for magnesium bromide, Cl2 is the formula for chlorine gas, Br2 is the formula for bromine gas, and MgCl2 is the formula for magnesium chloride.
Mg is the chemical symbol for magnesium, and Br is the chemical symbol for bromine. The numbers in the balanced equation indicate the number of atoms of the element they follow. These are typically written in subscript. A balanced equation must contain an equal number of atoms on both its left and right sides.