What is the correct formula for an ionic compound that contains aluminum ions and sulfide ions?
The answer is Al2S3. How did they get this answer?
To determine the correct formula for an ionic compound that contains aluminum ions (Al3+) and sulfide ions (S2-), we need to balance the charges of the ions.
The charge on the aluminum ion is +3, meaning that it has lost 3 electrons and has a positive charge. The charge on the sulfide ion is -2, indicating that it has gained 2 electrons and has a negative charge.
Since opposite charges attract each other, we need to find the smallest whole number ratio of aluminum and sulfide ions that balances their charges. In this case, we can achieve this balance by having two aluminum ions (+3 charge each) for every three sulfide ions (-2 charge each).
Thus, we can write the formula as Al2S3, where Al2 represents two aluminum ions and S3 represents three sulfide ions. This formula ensures that the positive charges from the aluminum ions (2 x +3 = +6) are balanced by the negative charges from the sulfide ions (3 x -2 = -6).