Question

Identify the element that has two electrons in the 'K' shell of its atom.

• A. Hydrogen
• B. He⁺
• C. Helium
• D. Aluminium

Answer 1

Answer: (C), (D)

The correct options are
C

Helium

D

Aluminium

Since the electrons in atoms are filled in the lower orbits first and then in higher energy orbits, all the atoms except for hydrogen will have two electrons in its 'K' shell as they will have more than two electrons (K shell cannot contain more than two electrons according to $2n^2$ rule) . But helium dipositive ion does not have any electrons.