What is the charge on a halide ion?

• A. -1
• B. 0
• C. +1
• D. -2

Answer: (A)

Halide ions form when a halogen gains one electron to fill its outer shell. Halogens have seven valence electrons, so by gaining one more they achieve a full octet. That extra electron gives the atom one more negative charge than positive, resulting in a -1 charge. For example, chloride (Cl⁻) is the common halide ion found in salts like sodium chloride. The charge wouldn’t be zero because the atom now has more electrons than protons, and it wouldn’t be +1 or -2 because halogens typically gain just one electron to reach a stable octet, producing a -1 charge.