What is the chemical formula for aluminum fluoride?
A) Al3F
B) AlF
C) AlF3
D) AlF3
The correct answer and explanation is:
The correct answer is C) AlF3.
Explanation:
Aluminum fluoride (AlF3) is an ionic compound composed of aluminum and fluorine. To determine its chemical formula, one must look at the charges of the constituent ions.
- Aluminum (Al) is in Group 13 of the periodic table, meaning it typically forms a cation with a +3 charge (Al³⁺).
- Fluorine (F) is in Group 17, and it typically forms an anion with a -1 charge (F⁻).
To form a neutral compound, the charges of the cations and anions must balance. For every Al³⁺ ion, three F⁻ ions are needed to balance the charge. This is why the formula for aluminum fluoride is AlF3.
The reason other options are incorrect:
- A) Al3F does not have the correct ratio of charges. The aluminum ion would need three fluorine ions to balance the +3 charge, making it incorrect.
- B) AlF also doesn’t balance the charges. The aluminum ion has a +3 charge, and one fluorine ion would only provide a -1 charge, which wouldn’t result in a neutral compound.
- D) AlF3 is repeated here, and as mentioned earlier, it is the correct formula.
Thus, AlF3 is the correct chemical formula for aluminum fluoride, reflecting the need for three fluoride ions to balance one aluminum ion in a neutral compound.