What is the electronic configuration of the element with atomic number 17?

What is the electronic configuration of the element with atomic number 17?

A. 1S^2 2S^2 2P^6 3S^2 3P^5

B. 1S^2 2S^2 2P^6 3S^2 3P^4

C. 1S^2 2S^2 2P^6 3S^2 3P^6 4d^1

D. 1S^2 2S^2 2P^6 3S^2 3P^6

E. 1S^2 2S^2 2P^5 3S^2 

Explanation:

Atomic number 17 is chlorine (Cl).
Chlorine has 17 electrons, which are filled according to the Aufbau principle.

Let’s check the correct configuration:

• 1s² → 2 electrons

• 2s² → 2 electrons (total = 4)

• 2p⁶ → 6 electrons (total = 10)

• 3s² → 2 electrons (total = 12)

• 3p⁵ → 5 electrons (total = 17)

✅ Correct Answer: A

A. 1s² 2s² 2p⁶ 3s² 3p⁵

Why the others are wrong:

• B → has only 16 electrons

• C → exceeds 17 electrons and incorrect orbital order

• D → represents argon (atomic number 18)

• E → incorrect filling of orbitals

✔️ Final Answer: A

QUESTION NUMBER TWO