Part A Why are the halogens among the most active nonmetals ? Why are the halogens among the most active nonmetals ? They only need one electron needed to attain a nobel gas configuration Their d orbitals are completely filled. All halogens have low electron affinities. They all have smaller diameters than other nonmetals. Their valence electrons are more effectively shielded.

They only need one electron needed to attain a nobel gas configuration

Explanation:

In the periodic table, HALOGENS are found in group 17 and it's consist of the following elements:Fluorine, chlorine, bromine, iodine. Astatine.

All these are known to be very active non metals because they only need one electron to attain a nobel gas configuration (stability). Atoms of elements consist of nucleus that is surrounded by electrons that moves around in orbitals. Valence electrons are those electrons found on the outermost shell of an atom and the reactivity of an atom is based on it. For an atom to be nonreactive it most have eight electrons in its outermost shell. All members of halogen family have seven valence electrons. Because they are very close to having a complete set of eight valence electrons, this makes them active.