The answer is (d).
Once again, start by identifying which energy level, and implicitly principal quantum number,
This time, you're dealing with the fourth energy level,
You already know that the number of orbitals thatcan be found in each energy level is given by the equation
#"no. of orbitals" = n^2#
In your case, the fourth energy level will contain
#n = 4 implies "no. of orbitals" = 4^2 = 16#
The number of subshells is given by the principal quantum number.
#"no. of subshells" = n#
In your case, the fourth energy level will have
#"no. of subshells" = 4#
subshells, each containing
- one 4s-orbital
- three 4p-orbitals
- five 4d-orbitals
- seven 4f-orbitals
Now, how about the number of electrons?
Well, each orbital can hold a maximum of two electrons, one having spin-up and one having spin-down.
This means that the maximum number of electrons a given shell, or energy level, can have is equal to
#"no. of electrons" = 2n^2#
In your case, the fourth energy shell will can hold a maximum of
#"no. of electrons" = 2 * 4^2 = "32 e"^(-)#
So, as a conclusion, all three options are corresct, which implies that the answer will be (d).