Ncert Exercises & Solutions

2.30 Explain, giving reasons, which of the following sets of quantum numbers are not possible.

(a) n = 0, l = 0, ml = 0, ms = + ½

(b) n = 1, l = 0, ml = 0, ms = – ½

(d) n = 2, l = 1, ml = 0, ms = – ½

(e) n = 3, l = 3, ml = –3, ms = + ½

(f) n = 3, l = 1, ml = 0, ms = + ½

(a) The given set of quantum numbers is not possible because the value of the principal quantum number (n) cannot be zero.

(b) The given set of quantum numbers is possible.

(c) The given set of quantum numbers is not possible.
For a given value of n, ‘l’ can have values from zero to (n – 1).
For n = 1, l = 0 and not 1.

(d) The given set of quantum numbers is possible.

(e) The given set of quantum numbers is not possible. For n = 3, l = 0 to (3 - 1) l = 0 to 2 i.e., 0, 1, 2

(f) The given set of quantum numbers is possible.