1. Determine the charges of the ions:
* Aluminum (Al) is in Group 3A of the periodic table, so it forms a +3 ion (Al³⁺).
* Oxygen (O) is in Group 6A of the periodic table, so it forms a -2 ion (O²⁻).
2. Find the least common multiple (LCM) of the charges:
* The LCM of 3 and 2 is 6.
3. Determine the subscripts:
* To achieve a +6 charge, we need two aluminum ions (2 x +3 = +6).
* To achieve a -6 charge, we need three oxygen ions (3 x -2 = -6).
4. Write the formula:
The formula for the ionic compound is Al₂O₃.
