Vsepr & Hybridisation

Question

Which statement best explains why PF5 is stable while NF5 is not?

RankGuru · Accepted Answer

1. **Valence Shells**: 
   - Nitrogen is in the 2nd period: Electron configuration $[He] 2s^2 2p^3$. It has **no $d$ orbitals** in its valence shell.
   - Phosphorus is in the 3rd period: Electron configuration $[Ne] 3s^2 3p^3$. It has vacant, low-energy **$3d$ orbitals**.
2. **Octet Expansion**: To form $5$ covalent bonds, an atom must accommodate $10$ electrons in its valence shell (expanded octet).
3. **Outcome**: Phosphorus can promote an electron to the $3d$ orbital and form $sp^3d$ bonds. Nitrogen is strictly limited by the 'Octet Rule' and cannot form 5 bonds.
4. **Sterics**: Additionally, Nitrogen is so small that having 5 large atoms around it would cause extreme steric repulsion.

Rank Guru

Vsepr & Hybridisation

Select the correct option:

Solution

🔒 Solution Hidden from View

More vsepr & hybridisation Practice Questions

Which statement about hydrogen bonding is correct?

Formal charge on oxygen in the nitrate ion (NO3−) using a structure with one double bond and two sin...

Which set lists increasing bond length for the carbon–oxygen bonds?

Which pair correctly matches molecule with geometry?

The approximate bond angle in NH3 is:

About This Question