Neutral Sodium Atom (Na):
– Sodium has an atomic number of 11, meaning it typically has 11 electrons distributed in different electron shells.
– The arrangement of electrons in sodium is 2, 8, 1 in the first three energy levels (K, L, and M shells).
– In the outermost shell (3rd shell), sodium has 1 electron.

Formation of Sodium Ion (Na+):
– Sodium tends to lose one electron to achieve a stable electron configuration, similar to the noble gas neon.
– When sodium loses an electron, it forms a positively charged ion, Na+, with 10 electrons.
– The electron configuration of Na+ shows completely filled K and L shells, resembling the arrangement of the noble gas neon (2, 8) which is stable.

Explanation for “Completely Filled K and L Shells” in Na+:
– The electron configuration of the sodium ion (Na+) after losing one electron becomes 2, 8, indicating that it has two electrons in the K shell and eight in the L shell.
– In this state, the K and L shells are considered “completely filled” within the remaining electrons of the ion, achieving a stable configuration similar to a noble gas.

Conclusion:
– While sodium as an atom doesn’t naturally have “completely filled” K and L shells, its ion (Na+) achieves a stable electron configuration resembling the noble gas neon by losing one electron and leaving behind a configuration with filled K and L shells.

This process of ionization helps sodium reach a stable state similar to a noble gas, making the Na+ ion more chemically stable than the neutral sodium atom.