Question

For each of the following pairs of ions, write the formula of the compound they will form:

a) Na+ and Cl–
b) Mg²+ and O³–
c) Al³+ and N³–
d) K+ and S²–

Answer 1

The formulas for the compounds are NaCl, AlN, and K2S. There is an error with the pairing of Mg2+ and O3-, as these ions cannot form a neutral compound due to mismatched charges.

Step-by-step explanation:

When writing the formula for compounds formed by ions, we need to ensure the total charge in the compound is neutral. This often involves finding the smallest numbers of each ion that will balance the charges.

• (a) When Na+ and Cl− combine, they form sodium chloride with the formula NaCl.
• (b) Mg2+ and O3− cannot form a compound directly because their charges do not balance. This seems to be an error.
• (c) When Al3+ and N3− combine, they form aluminum nitride with the formula AlN.
• (d) When K+ and S2− combine, they form potassium sulfide with the formula K2S.