Which of the following is non – permissible? 

According to the rules for quantum number the possible values of n, l, m and s are

n = 1 to any whole number.

            l = 0 to (n – 1) for every value of n, m = - 1 to 0 to + 1, for every value of l, and 

(a)    n = 4, l = 3, m = 0

All the values are according to rules.

(b)   n = 4, l = 2, m = 1

All the values are according to rules.

(c)    n =4, l = 4, m = 1

             The value of l can have maximum (n – 1) value, i.e. 3 in this case.

            This set of quantum numbers is non – permissible

(d)   n = 4, l = 0, m = 0

All the values are according to rules

            Choice (a), (b) and (d) are permissible.