You're absolutely right! When sodium (Na) reacts with chlorine (Cl) to form sodium chloride (NaCl), the resulting ions have electron configurations that are the same as noble gas atoms. Here's why:

Sodium (Na)

* Original electron configuration: 1s² 2s² 2p⁶ 3s¹

* Losing one electron: To achieve a stable octet (like the noble gas neon), sodium loses the single electron in its outermost shell.

* Sodium ion (Na+) electron configuration: 1s² 2s² 2p⁶ (This is the same as neon's configuration)

Chlorine (Cl)

* Original electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁵

* Gaining one electron: Chlorine needs one more electron to complete its octet (like the noble gas argon).

* Chloride ion (Cl-) electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ (This is the same as argon's configuration)

The Key Takeaway

Atoms tend to gain or lose electrons to achieve the stable electron configuration of the nearest noble gas. This is the driving force behind ionic bonding, where the electrostatic attraction between oppositely charged ions holds the compound together.