Question

which electron configuration belongs to chlorine (cl)? 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 3p5 1s2 2s2 2p6 3s2 3p7

Explanation:

Step1: Recall chlorine's atomic number

Chlorine has an atomic number of 17, meaning it has 17 electrons.

Step2: Analyze electron - configuration rules

Electrons fill orbitals in the order 1s, 2s, 2p, 3s, 3p etc. The s - orbital can hold 2 electrons, the p - orbital can hold 6 electrons.

Step3: Calculate electrons in each configuration

For the configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$:

• In 1s: 2 electrons.
• In 2s: 2 electrons.
• In 2p: 6 electrons.
• In 3s: 2 electrons.
• In 3p: 5 electrons.
• Total electrons: $2 + 2+6 + 2+5=17$

Answer:

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