Question

Metals lose electrons under certain conditions to attain a noble gas electron configuration. How many electrons must be lost by the element Li? number of electrons: Which noble gas electron configuration is attained in this process? O krypton O neon O argon O xenon O radon O helium

Answer 1

To answer this question, look at the electronic configuration of Li:

It’s atomic number is 3, so it has 3 electrons in the atom.

Filling up the electrons: 1s²2s¹

A noble gas has an outer shell which is fully filled. Looking at the electronic configuration for Li, to get an outer shell which is fully filled, we can either:

1. Lose the 2s¹ electron to get 1s²(since 1s doesnot have p orbital, 1s² denotes a fully filled shell)
2. Add another electron to 2s, and 6 more to 2p to get 2s²2p⁶ . Adding so many electrons is obviously energetically unfavourable.

So, 1 electron has to be lost by Li. Since the closed shell obtained has n = 1 (1s), it wil correspond to the 1^st inert gas in the group, i.e Helium (He).