WAEC Chemistry 2020 Paper

Concept:Group VII elements are known as halogens in their free elemental state, but in combined state they form halides.Explanation:Group VII elements (such as fluorine, chlorine, bromine, and iodine) exist as diatomic molecules $\mathrm{F}_2$, $\mathrm{Cl}_2$, $\mathrm{Br}_2$, and $\mathrm{I}_2$ in their free state.When these elements react with another element or group, they accept one electron to form negatively charged ions or become part of a binary compound.These combined forms are called halides.For example, sodium chloride ($\mathrm{NaCl}$) is a halide because it contains chlorine in a combined state.Thus, halide refers to any binary compound of a halogen or the halide ion $\mathrm{X}^-$.Answer:C. Halide