How many d orbitals can there be in one energy level?

1 Answer
Jul 20, 2016

This depends on the number of magnetic quantum numbers ml that correspond to a single angular momentum quantum number l.

  • n is the principal quantum number (the energy level) going as 1,2,3,...,N, and N is a large integer. For one energy level, n is only one number at a time.
  • l is the angular momentum quantum number, and it goes as 0,1,2,...,n1. For one subshell, l is only one number at a time, and l=0,1,2,3,4... corresponds to the s,p,d,f,g,... subshells. However, there can be more than one l for the same energy level.
  • ml is the magnetic quantum number, and takes on all numbers in the set {l,l+1,...,0,...,+l1,+l}. It corresponds to how many orbitals are in a subshell.

For an energy level to validly have d orbitals, n3. Any smaller n, and the number of d orbitals is 0.

For any n, l(n1) is allowed, and for d orbitals, l=2 (of course, 2=31, so that's why n3 for d orbitals). Therefore, what we have for ml is:

ml={2,1,0,+1,+2}

So, there are 2l+1=5 different (but degenerate, same in energy) d atomic orbitals in the same nd subshell.

Example

3dxy, 3dxz, 3dyz, 3dx2y2, 3dz2:

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