Question

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

Explanation:

Step1: Understand electron - loss concept

When an atom loses electrons, it forms a positive ion (cation). The charge of the ion is equal to the number of electrons lost.

Step2: Determine the charge of mercury ion

Mercury (Hg) loses 2 electrons. Since each electron has a charge of - 1, losing 2 electrons gives a charge of + 2.

Answer:

Hg$^{+2}$