What is the smallest possible value of the principal quantum number n for an f electron?

For the f electron, the smallest possible principal quantum number is 4.

The principal quantum number is the shell of the atom for the electrons spinning. The electrons are to be distributed on the quantum numbers. The n is the principal quantum number and is the shell.

n can be 1, 2,3,4,5,6, or 7.

The shells are further divided into orbitals.

n = 1 = s

n =2 = s, p

n = 3 = s, p, d

n = 4, 5, 6, 7 = s, p, d, and f.

Thus for the f electron, the smallest possible principal quantum number is 4.

For more information about the principal quantum numbers, refer to the link:

link