Answer:
b. Halogens
Explanation:
Chemical reactions are associated with the 'breaking' of old bonds and formation of new bonds. Since valence electrons are the ones that participate bonding, therefore the reactivity of elements must depend on the ease with which these electrons can be lost or gained.
Noble gases have fully filled (n²np⁶) valence electron configuration and are highly stable and inert.
Carbon family have less that half filled p-orbitals (ns²np²) in their valence configuration and are not very reactive. Metalloids have their reactivity in between metals and non-metals.
Halogens in contrast have a valence electron configuration of ns²np⁵. They only need one more electron to complete their octet and become stable. As a result they are highly reactive i.e. they readily attract electrons and form new bonds.
