Question #c7c7e

1 Answer
Oct 14, 2015


The answer is (d).


Once again, start by identifying which energy level, and implicitly principal quantum number, #n#, corresponds to the #N# shell.

This time, you're dealing with the fourth energy level, #n=4#.

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).