The Octet Rule Game
Arrange electrons to achieve stability
What this lesson covers
Why it matters
Sodium isn't trying to befriend chlorine — it is desperate to hand over its single outer electron, emptying that shell to reach a stable, noble-gas-like core.
Predict first
Why does sodium readily give up its single outer electron?
By losing one electron, sodium reveals the full, stable octet of its inner shell, mimicking the noble gas neon.
- It wants to achieve a stable octet in its second shell — correct
- It wants to become larger in size
- It is repelled by the nucleus
- It wants to share electrons equally
What you do
Build a sodium atom — 11 protons, 12 neutrons, electrons arranged 2,8,1. Spot the lone outer electron: that's the one sodium gives away to become Na⁺.
Check yourself
What is the electron configuration of the sodium ion (Na⁺)?
Na (2,8,1) loses 1 electron to become Na⁺ (2,8), achieving a stable octet.
Why does chlorine gain an electron?
Chlorine (2,8,7) needs one more electron to reach the stable 2,8,8 configuration of argon.
- 2, 8, 1
- 2, 8 — correct
- 2, 8, 8
- To complete its octet and become stable — correct
- To become positively charged
- To reduce its atomic number
- To make its shell empty