Chemistry · CHEMICAL BONDING AND MOLECULAR STRUCTURE

Refer to the shapes of molecules with no lone pairs shown in Fig. 4.6 (\( \text{BeCl}_2 \), \( \text{BF}_3 \), \( \text{CH}_4 \), and \( \text{PCl}_5 \)). In \( \text{PCl}_5 \), two different bond angles (\( 90^\circ \) and \( 120^\circ \)) are depicted. Why do axial and equatorial bonds in this molecule experience different extents of repulsion according to VSEPR theory?

1. Axial bond pairs suffer repulsions from only two equatorial bond pairs at \( 90^\circ \).
2. Each axial bond pair experiences repulsion from three equatorial bond pairs at \( 90^\circ \), which is greater than the repulsions experienced by equatorial bond pairs.
3. Equatorial bond pairs suffer repulsions from four equatorial bond pairs at \( 120^\circ \).
4. Axial bonds are shorter than equatorial bonds, forcing the electron pairs closer to the phosphorus atom.