Question

Describe how electrons in an atom are arranged in different shells.

Answer 1

The maximum number of electron in a shell is suggested by the formula = 2n²

in 1st shell maximum number of electrons is = 2 x 1² = 2

in 2nd shell maximum number of electrons is = 2 x 2² = 8

in 3rd shell maximum number of electrons is = 2 x 3² = 18

in 4th shell maximum number of electrons is = 2 x 4² = 32

Answer 2

There are basically five rules---

1) The maximum number of electrons present in a shell is given by formula 2n^2, where n is the energy level 1,2,3....
For example, the maximum number of electrons that can be accommodated in following are --
K shell = 2 x (1)^2 = 2
L shell = 2 x (2)^2 = 8
M shell = 2 x (3)^2 = 18
N shell = 2 x (4)^2 = 32 and it goes on.

2) The maximum number of electrons that can be accommodated in outermost shell is 8.

3) Electrons are accommodated in a step wise manner.The outer shells are not filled until the inner shells are complete.

4) The second last shell , or the penultimate shell can accommodate only 18 electrons.

5) The third last shell, or anti - penultimate shell can accommodate only 32 electrons.