Question

why is helium less reactive than hydrogen?
a. each helium atom has a full protonic power level, but each hydrogen atom only has one proton
b. each helium atom has two electron energy levels, but each hydrogen atom only has one electron energy level
c. each helium atom has four neutrons, but each hydrogen atom only has one neutron
d. each helium atom has a full valence electron shell, but each hydrogen atom only has one valence electron

Explanation:

The reactivity of an element is related to its valence - electron configuration. Helium has 2 electrons which fill its first (and only) electron shell, giving it a stable full - valence electron shell. Hydrogen has 1 valence electron and is more likely to participate in chemical reactions to achieve a stable electron configuration.

Answer:

D. Each helium atom has a full valence electron shell, but each hydrogen atom only has one valence electron