Question

An element has three electron in the 4 th shell, the atomic number of the element is
(a) 13
(b) 21
(c) 27
10) 31​

Answer 1

Explanation:

1. An element has three (3)

Electrons in the fourth shell, the atomic number of the element is 21

Answer 2

Answer:

(c)21

Explanation:

as we know,

in the 1st shell,there are two electrons

in 2nd,3rd, and 4th ,, there is possibility of 8 electrons in each.

As fourth shell has 3 electrons,so the atomic no. is

2+8+8+3=21