Question

Which of the following spectroscopic notations are allowed (that is, which violate none of the rules regarding values of quantum numbers)? Select all that apply.

a. 5i^8

b. 5f^10

c. 4f^15

d. 2s^1

e. 6g^1

Answer 1

All notations are allowed except a. 5i⁸ and c. 4f¹⁵.

The spectroscopic notation is written as ''.

Where n is principle quantum number, l is orbital angular momentum quantum number (denotes s, p, d, f,... orbitals), k is the number of electrons in the orbital.

The value of 'l' can vary from -(n-1) to +(n-1). ,

l = 0 denotes 's' orbital, l= 1 denotes 'p' , l=2 denotes 'd'.. l =3 denotes 'f', then 'g' , then 'h', then 'i' and so on.

Each of these orbitals can contain a maximum of '2(2l+1)' electrons. i.e.

The s-orbital can contain a maximum of

                                             2(2x0+1) = 2 electrons.

Similarly, p, d, f, g, h, i can contain a maximum of 6, 10, 14, 18, 22, 26 electrons respectively.

Hence, it is clear that, option 'a. 5i⁸' and 'c. 4f¹⁵' are incorrect. Because 'f' orbital can not have more than 14 electrons and n =5 can not have 'i_th' orbital.