Question

what is the electron configuration of chlorine (cl)?
○ $1s^2 2s^2 2p^6 3s^2 3p^3$
○ $1s^2 2s^2 2p^6 3s^2 3p^5$
○ $1s^2 2s^2 2p^6 3s^2 4s^2 3p^3$
○ $1s^2 2s^2 2p^6 3s^2 3p^2 3d^3$

Explanation:

Chlorine (Cl) has an atomic number of 17, meaning it has 17 electrons. The electron configuration follows the Aufbau principle, filling orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, etc. The 1s orbital holds 2 electrons, 2s holds 2, 2p holds 6, 3s holds 2, and then the remaining 5 electrons go into the 3p orbital. So the correct configuration is \(1s^2 2s^2 2p^6 3s^2 3p^5\).

Answer:

B. \(1s^2 2s^2 2p^6 3s^2 3p^5\)