Respuesta :

The orbitals are 1s, 2s, 2p, 3s, 3p, 3d, 4,s 4p, 4d, 4f, 5s, 5p, 5d, 5f, 6s, 6p, 6d, 7s, and 7p.

The one that doesn't exist is d) 1d.