* Electronic Configuration: Sodium has an electronic configuration of 1s² 2s² 2p⁶ 3s¹. It has one electron in its outermost shell (valence shell). To achieve a stable octet, it tends to lose this one electron, becoming a positively charged ion (Na⁺).
* Ionic Bonding: Sodium chloride (NaCl) forms through ionic bonding. Sodium loses its one electron to chlorine, which has seven electrons in its outermost shell. Chlorine gains this electron to complete its octet, becoming a negatively charged ion (Cl⁻).
* Electrostatic Attraction: The oppositely charged ions (Na⁺ and Cl⁻) attract each other strongly, forming a crystal lattice structure. The ionic bond is a result of this electrostatic attraction.
Why not +4?
* Energy Requirements: For sodium to achieve a +4 valency, it would need to lose four electrons. This would require a significant amount of energy, making it highly unlikely to occur.
* Stability: A +4 valency would leave sodium with a very unstable configuration, far from the stable octet rule.
In summary: Sodium's electronic configuration and the nature of ionic bonding lead to a +1 valency in NaCl, resulting in a stable and energetically favorable compound.
