Chem — Atomic Structure and Periodicity + 4 more topics

• s-orbitals are spherical and can hold 2 electrons. (1 orbital in an s subshell)
• p-orbitals are dumbbell-shaped and can hold 6 electrons. (3 orbitals in a p subshell)
• d-orbitals have more complex shapes and can hold 10 electrons. (5 orbitals in a d subshell)
• f-orbitals are even more complex and can hold 14 electrons. (7 orbitals in an f subshell)

The order of filling is generally 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, etc.