Giselle is pairing ions to create stable binary ionic compounds. She knows that the sum of charges of the two ions must be zero in order for the compound to be stable. Which ion could be paired with a potassium ion, K+, to form a stable binary compound?

Question

A beryllium, Be2+

B. fluorine, F−

C. lithium, Li+

D. oxygen, O2−

Answer 1

The correct answer is A. beryllium, Be2+.

When pairing ions to form a stable binary ionic compound, the sum of the charges of the two ions must be zero.

In this case, the potassium ion has a charge of +1 (K+), so in order to form a stable compound, it needs to pair with an ion that has a charge of -1.

Among the given options, only the beryllium ion, Be2+, has a charge of +2, which balances out the charge of the potassium ion. Thus, the combination of K+ and Be2+ will result in a stable binary ionic compound.