Here's how to write the balanced chemical equation for the reaction of aluminum and chlorine:

1. Identify the reactants and products:

* Reactants: Aluminum (Al) and Chlorine gas (Cl₂)

* Product: Aluminum chloride (AlCl₃)

2. Write the unbalanced equation:

Al + Cl₂ → AlCl₃

3. Balance the equation:

* Aluminum (Al): There's one Al on each side, so it's balanced.

* Chlorine (Cl): There are two Cl atoms on the left and three on the right. To balance, we need to use coefficients.

* Put a 2 in front of AlCl₃: Al + Cl₂ → 2AlCl₃

* Put a 3 in front of Cl₂: Al + 3Cl₂ → 2AlCl₃

* Now the equation is balanced!

The balanced chemical equation is:

2Al + 3Cl₂ → 2AlCl₃