This is an **oxidation-reduction** (redox) reaction:

* 2 Br0 + 2 e- → 2 Br-I (reduction)*

* Mg0 - 2 e- → MgII (oxidation)*

*Br2* is an **oxidizing** agent, *Mg* is a **reducing** agent.

### Word equation

* Magnesium + bromine → magnesium bromide*

### Input interpretation

* Mg + Br2 → MgBr2*

* Magnesium bromine magnesium bromide*

### Balanced equation

Balance the chemical equation algebraically:

* Mg + Br2 → MgBr2*

Add stoichiometric coefficients, c,, to the reactants and products:

* c1Mg + c2Br2 → c3MgBr2*

Set the number of atoms in the reactants equal to the number of atoms in the products for Mg and Br:

*Mg: c1 = c3*

*Br: 2c2 = 2c3*

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:

** *** c1=1 c2=1*

* c3 = 1*

Substitute the coefficients into the chemical reaction to obtain the balanced equation:

Answer:

* Mg + Br2 → MgBr2*