How many orbitals are in the third principal energy level​

The third principal energy level has s, p and d subshell.

s contains 1 orbital.  

p contains 3 orbitals.

d contains 5 orbitals.

Together they 3rd energy level can bear 18 electrons.

The energy levels are quantized, that means electrons spinning inside a particular orbitals will have a particular energy. As long as that electron's energy remains unchanged (no absorption or release of energy), the electron is confined within the orbital it is staying.

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