Question

The correct set of quantum numbers for an element (Z=17) for the unpaired electron will be

• A. 3, 1, 1, 1/2
• B. 2, 0, 0, 1/2
• C. 3, 0, 0, 1/2
• D. 2, 1, 1, 0

Hint:

The quantum numbers describe the state of an electron in an atom, and for an unpaired electron, \( l = 1 \) corresponds to a p orbital.

Answer 1

The Correct Option is A

The electron configuration for the element with atomic number Z = 17 (Chlorine) is: \[ 1s^2 2s^2 2p^6 3s^2 3p^5 \] The unpaired electron in the 3p orbital has the following quantum numbers: - Principal quantum number \( n = 3 \) (since it is in the third shell) - Azimuthal quantum number \( l = 1 \) (since it is in a p orbital) - Magnetic quantum number \( m_l = 1 \) (can take values between \(-l\) and \(+l\)) - Spin quantum number \( m_s = \pm \frac{1}{2} \) (the electron has a half-spin) Thus, the correct set of quantum numbers is (a).