Question

The electron configuration `1s^2 2s^2 2p^6 3s^2 3p^6` represents which noble gas?

Answer 1

Argon (Ar)

Explanation:

The given electron configuration means that the element has 18 electrons - 2 in the first energy level and in the 2 orbital, 8 in the second energy level of which 2 in the s orbital and 6 in the p orbital, and same for the third energy level.

Consultation of the periodic table shows this element to be Argon (Ar) occurring in period 3 and group 8, ie the group of noble gases, who all have filled outermost energy levels and are hence very stable and rather unreactive.