To determine the correct formula for aluminum chloride, we need to consider the valences of aluminum and chlorine. Valence refers to the combining capacity of an element, which is determined by the number of electrons it can lose, gain, or share to form a chemical bond.
1. Identify the valences of the elements:
- Aluminum (Al) has a valence of +3, meaning it can lose three electrons.
- Chlorine (Cl) has a valence of -1, meaning it can gain one electron.
2. Determine the ratio for a neutral compound:
- For the compound to be neutral, the total positive charge must balance the total negative charge.
- Since aluminum has a +3 charge, one aluminum ion can balance three chlorine ions, each with a -1 charge.
3. Write the chemical formula:
- The formula of a compound is written by placing the chemical symbols for the elements together, with the number of each type of atom indicated by a subscript.
- One aluminum atom (Al) combines with three chlorine atoms (Cl) to balance out the charges, resulting in the formula [tex]\( \text{AlCl}_3 \)[/tex].
Therefore, the correct formula for aluminum chloride is written as [tex]\( \text{AlCl}_3 \)[/tex].
So, the best answer to the question is:
A. [tex]\( \text{AlCl}_3 \)[/tex]
