Which of the noble gases has the greatest ionization energy

A.

He

B.

Xe

C.

Ar

D.

Rr

Correct answer is A

Ionization energy: The amount of energy required to remove an electron from an isolated atom or molecule.

Trends down group :

  • Ionization energy decreases down the group.
  • This is due to the shielding or screen effect of the outer electrons from the nucleus.
  • The attraction is weaker and they are more easily removed.
  • Helium and radon both belong to group 8 which are called noble gases.
  • Helium (He) has the highest ionization energy and Radon (Rn) has the lowest ionization energy.