Why is helium less reactive than hydrogen?
A. Each helium atom has a full valence electron shell, but each hydrogen atom only has
one valence electron.
B.
Each helium atom has four neutrons, but each hydrogen atom only has one neutron.
Each helium atom has a full protonic power level, but each hydrogen atom only has
one proton.
D.
Each helium atom has two electron energy levels, but each hydrogen atom only has
one electron energy level.