What is the electron configuration of chlorine (Cl)?

Chlorine has atomic number 17, so a neutral chlorine atom has 17 electrons. Filling orbitals in order gives 1s² 2s² 2p⁶ 3s² 3p⁵, for a total of 17 electrons. Therefore, the correct choice is B, 1s²2s²2p⁶3s²3p⁵.

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