Question

A neutral atom of an element has 2K, 8L and 5M electrons. What is the maximum number of electrons having same spin?

• A. 5
• B. 8
• C. 9
• D. 3

Answer 1

The correct option is C 9

The number of electrons in the shells is given as 2 in K shell, 8 in L shell and 5 in the M shell. Thus, the atom has in total of 2+8+5=15 electrons.

This means that the atom is phosphorus.

The electronic configuration will be as follows.

$1s^{2}2s^{2}2p^{6}3s^{2}3p^3$

As we can see clearly in the image given that the maximum number of electrons having the same spin are 9.