Question

Which of the following is the outermost shell for elements of period 2?

• A. K shell
• B. L shell
• C. M shell
• D. N shell

Answer 1

The correct option is B

L shell

Explanation for correct option:

B. L shell

Period in periodic table:

• There is a total of $7$ periods in a periodic table.
• “An electron shell is an orbit followed by electrons around an atom's nucleus.”
• The nearest shell to the nucleus is called the “K shell”, followed by the “L shell” which is the second shell, then the “M shell” i.e. the third shell, and so on.
• For period 2, the outermost shell is L-shell as it comprises two shells.
• For example, Flourine$\left(\mathrm{F}\right)$ is an element belonging to period 2, it has an atomic number $9$ and the electrons per shell in the case of Flourine are $2,7$. $2$ electrons in K-shell while $7$ electrons in the L-shell.
• Thus, for period 2, the outermost shell is L-shell.

Explanation for incorrect options:

For period 2, the outermost shell is L-shell. Thus, options A, C, and D are incorrect.

Hence, the correct option is B i.e. L-shell.