Question

Which of the following orbital does not make sense ?
(A) 3d (B) 2 f
(C) 5 p (D) 7s

Answer 1

Answer:

(B) 2f

This is because 'f' orbital does not exist in second shell.

Answer 2

Answer: 2f does not make sense.

Explanation:

About quantum numbers:

• Quantum numbers are the set of 4 numbers that tells us about the position and energy of an electron in an atom.
• The 4 quantum numbers are:

1. Principal quantum number (n)
2. Azimuthal quantum number (l)
3. Magnetic quantum number (m)
4. Spin quantum number (s)

Azimuthal quantum number (l)

• Tells us about the orbital of the electron.
• The value of l lies between 0 - n-1
• l = 0 ; s
• l = 1 ; p
• l = 2 ; d
• l = 3 ; f

In the question:

       For 2f, the value  of:

• n = 2
• l can 0,1.
• But for f orbital l = 3, which is not possible in this case.
• 3d, 5p,7s all obey the rule of quantum numbers.

Thus 2f does not make sense.

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