**(i)** The number of electrons in any orbit can be determined by the general formula 2(n^{2}), where n = 1, 2, 3….. and so on. Here **‘**n**’** represents the number of shell like 1 for the first, 2 for the second and so on.

**(ii)** So to determine the maximum number of electron in any orbit we can use the formula 2(n^{2}).

**(iii) **For first orbit n = 1 maximum electron are 2(1^{2}) = 2 electrons.

**(iv)** Similarly if we take third or fourth shell n = 3 or 4, maximum electrons will be 2(3^{2}) = 18 and 2(4^{2}) = 32.

**(v) **For n = 4 the maximum electrons come out to be 32 and for n = 3 it is 18 but that is not possible as the repulsion forces between the electrons will be very large and the atom will become unstable.

**(vi)** So maximum number of electrons in any outermost orbit cannot be more than 8, because of the octet rule which states maximum 8 electrons can be present in any orbit for the atom to be stable.