Here's why:
* Nitrogen's electronegativity: Nitrogen is more electronegative than sulfur. This means it attracts electrons more strongly, making it harder for nitrogen to form six bonds with fluorine.
* Nitrogen's valency: Nitrogen has a valency of 3, meaning it can form a maximum of three covalent bonds.
* Sulfur's valency: Sulfur has a valency of 6, making it capable of forming six bonds with fluorine.
* Stability of SF6: SF6 is a stable molecule due to the large size of the sulfur atom and the strong electronegativity of fluorine. The six fluorine atoms surround the sulfur atom in a symmetrical octahedral arrangement, resulting in a stable structure.
Therefore, the formation of NF3 and SF6 can be explained based on the electronegativity and valency of the central atom, along with the stability of the resulting molecule.
