Question

what ion is formed when an atom of mercury (hg) loses two electrons?
hg⁻¹
hg⁻²
hg⁺¹
hg⁺²

Explanation:

When an atom loses electrons, it forms a positively - charged ion (cation). The number of electrons lost corresponds to the positive charge on the ion. Here, mercury (Hg) loses two electrons. So the ion formed will have a charge of + 2.

Answer:

Hg⁺²