Most non-metallic among F, Cl, Br, I, and At is:
Cl
At
F
I
Fluorine is most non-metallic among F, Cl, Br and At. This is because metallic character decreases across a period and increases down a group.
Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy ) is (a) F > Cl > Br > I (b) F < Cl < Br < I (c) F < Cl > Br > I (d) F < Cl < Br < I