Question

write the electron configuration for a neutral atom of chlorine.

Explanation:

Step1: Find chlorine's atomic number

Chlorine (Cl) has an atomic number of 17, so a neutral atom has 17 electrons.

Step2: Fill orbitals by Aufbau principle

Fill lower energy orbitals first: 1s (max 2 e⁻), 2s (max 2 e⁻), 2p (max 6 e⁻), 3s (max 2 e⁻), then remaining electrons go to 3p.
Electrons used so far: $2+2+6+2=12$, remaining electrons: $17-12=5$

Step3: Assemble full configuration

Combine the filled orbitals with their electron counts.

Answer:

$1s^2 2s^2 2p^6 3s^2 3p^5$