10. What are the ideal bond angles between the phosphorus:hydrogen bonds for the PH_(3) molecule? __

The molecule, also known as phosphine, has a trigonal pyramidal shape due to the presence of a lone pair on the phosphorus atom. This geometry is similar to that of ammonia ( ). In an ideal tetrahedral arrangement, the bond angles would be approximately 109.5 degrees. However, due to the lone pair-bond pair repulsion being greater than bond pair-bond pair repulsion, the bond angles in are slightly less than 109.5 degrees.In reality, the bond angle in is around 93.5 degrees. This deviation from the ideal tetrahedral angle is due to the lone pair on phosphorus, which exerts more repulsion on the bonding pairs, compressing the bond angles between the hydrogen atoms.