State the three rules proposed by Bohr and Bury, regarding the distribution of electrons in different orbits of an atom - CBSE Class 9 Science - Learn CBSE Forum

The maximum number of electrons occupied by K and L-shells are 2 and 8 respectively and there are 4 electrons in the M-shell of the atom. Therefore, the electronic configuration of this element is 2, 8, 4.
The total number of electrons = 2 + 8+ 4 = 14. In a neutral atom, number of electrons is equal to the number of protons. Therefore, the atomic number of this element is 14.

As Z = 3, therefore electronic configuration =2,1. It has one valence electron. Therefore, its valency is equal to one. The element having atomic number three is lithium (Li).The three rules are:

The maximum number of electrons present in a shell is given by the formula 2n2, where n is the orbit number or energy level, i.e. 1, 2, 3 …, therefore, the maximum number of electrons in
different shells are as follows :
First orbit or K-shell = 2 x 1^{2} = 2
Second orbit or L-shell = 2 x 2^{2} = 8 and so on.

The maximum number of electrons that can be accommodated in the outermost orbit is 8.

Electrons are not accommodated in a given shell, unless the inner shells are filled, i.e. shells are