Question

which of the following is not an allowed value of the principal quantum number
a 500,000
b 10
c 2
d 0
continue
question 4 of 9

Explanation:

The principal quantum number (\(n\)) must be a positive integer (i.e., \(n = 1, 2, 3, \dots\)). It cannot be zero or a negative number. Among the options, 0 is not a positive integer, so it's not an allowed value for the principal quantum number. Options A (500,000), B (10), and C (2) are positive integers and thus allowed.

Answer:

D. 0