Allowed quantum numbers
Which set of quantum numbers (n, l, ml) is NOT allowed?
Answer A: explanation for every choice
A
Correct. l can range only from 0 to n − 1, so n = 2 allows l = 0 or 1.
B
This is a valid 3d orbital.
C
This is a valid 2p orbital.
D
This is the 1s orbital.
Takeawayl = 0 … n − 1; ml = −l … +l.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID cp96.