Question

Which of the following is/are possible?

• A. 3f
• B. 4d
• C. 2d
• D. 3p

Answer 1

Answer: (B), (D)

The correct options are
B 4d
D 3p

Angular quantum number(l) may have value less than the principal quantum number.
For a principle quantum number n there should be n-1 number of orbitals(l) are present(l=0,1,2,3 indicates s,p,d & f orbitals)
For n -1 (l=0 indicates s orbital)only s orbital is present.
For n -2 (l=0,1 indicates s,p orbital) only s and p orbitals are present.
For n -3 (l=0,1,2,indicates s,p,d orbital) only s ,p and d orbitals are present.
For n -4 (l=0,1,2,3 indicates s,p,d,f orbital) only s ,p,d and f orbitals are present.
Hence options $B$ & $D$ are correct.