Enter the correct ionic formula for the compound formed between the following.Al3+ and Cl−Express your answer as a chemical formula.
T he Correct Answer and Explanation is :
Correct Ionic Formula:
AlCl₃
Explanation
The correct ionic formula for the compound formed between Al³⁺ (aluminum ion) and Cl⁻ (chloride ion) is AlCl₃.
To determine the correct ionic formula, we need to balance the total positive and negative charges so that the resulting compound is electrically neutral. Aluminum, a metal from group 13 of the periodic table, forms a cation with a +3 charge (Al³⁺). Chlorine, a nonmetal from group 17 (the halogens), gains one electron to form a −1 anion (Cl⁻).
Each Al³⁺ ion contributes +3 charge, and each Cl⁻ ion contributes −1 charge. To balance the charges, we need three Cl⁻ ions for every one Al³⁺ ion, because:
- Total positive charge from 1 Al³⁺ = +3
- Total negative charge from 3 Cl⁻ = 3 × (−1) = −3
- Combined: +3 + (−3) = 0 → neutral compound
Therefore, the correct ratio of aluminum to chlorine ions is 1:3, and the empirical formula is written as AlCl₃.
This compound is held together by ionic bonds, which are electrostatic attractions between oppositely charged ions. In solid aluminum chloride, these ions arrange themselves into a crystal lattice to maximize attraction and minimize repulsion, resulting in a stable structure.
In aqueous solution or molten form, AlCl₃ dissociates into Al³⁺ and Cl⁻ ions, allowing it to conduct electricity, a characteristic of ionic compounds.
It’s important not to write the formula as AlCl or AlCl₂, as these do not balance the charges correctly:
- AlCl: +3 − 1 = +2 → not neutral
- AlCl₂: +3 − 2 = +1 → not neutral
Only AlCl₃ gives a neutral compound, making it the correct ionic formula.
