# How can I write the formula for aluminum chloride?

Jun 3, 2018

${\text{AlCl}}_{3}$
We know that aluminum has a valency of $+ 3$ because it has three valence electron which it can lose easily. Similarly, chlorine has a valency of $- 1$ because it can gain an electron.
["Al"]^(3+) + 3["Cl"]^(-) -> "AlCl"_3