Which set of quantum numbers is not permitted?
Correct answer: C. n equals 2, l equals 2, m equals 1
- A. n equals 2, l equals 1, m equals 0
- B. n equals 3, l equals 2, m equals minus 2
- C. n equals 2, l equals 2, m equals 1
- D. n equals 1, l equals 0, m equals 0
Explanation
The azimuthal quantum number can never equal or exceed n, so l equal to 2 is impossible when n is 2, which would describe a non existent 2d orbital. The other three sets satisfy every restriction. Checking l against n first, then m against l, catches almost every invalid set.
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About Quantum Numbers
Quantum numbers describe an electron's energy level, subshell, orbital orientation and spin. You examine the principal, azimuthal, magnetic and spin quantum numbers, their allowed values, orbital capacity and how they determine electronic configurations and distinguish electrons within an atom.
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