Question

what is the formula for the ionic compound aluminum oxide?\
\bigcirc alo\
\bigcirc $\ce{al_{2}o_{2}}$\
\bigcirc $\ce{al_{3}o_{2}}$\
\bigcirc $\ce{al_{2}o_{3}}$\
\bigcirc $\ce{al_{3}o}$

Explanation:

To determine the formula for aluminum oxide, we first identify the ions involved. Aluminum (Al) typically forms a \( \text{Al}^{3+} \) ion, and oxygen (O) typically forms an \( \text{O}^{2-} \) ion. To balance the charges in an ionic compound, we use the criss - cross method. The charge of the aluminum ion (3+) becomes the subscript of oxygen, and the charge of the oxygen ion (2 -) becomes the subscript of aluminum. So we get \( \text{Al}_2\text{O}_3 \) (since 3 (from Al) and 2 (from O) cross - multiply, and we simplify if possible; here, 3 and 2 have no common factor other than 1).

Answer:

D. \( \text{Al}_2\text{O}_3 \) (assuming the last option with the correct formula is labeled as such, but based on the options, the correct one is \( \text{Al}_2\text{O}_3 \))