Question

The correct order of bond angle

(1) PF3<PCl3<PBr3<PI3 .

(2) PI3<PCl3<PBr3<PF3 .

(3) PF3<PBr3<PCl3<PI3 .

(4) PF3<PCl3<PI3<PBr3 .

Answer 1

Phosphorus has a 3 outer shell. The outermost shell comprises a total of five electrons, with two electrons in 3s and three electrons in 3p. shell. Three of the five electrons are bound to three halide atoms, leaving two electrons unattached. sp3 is the central atom of phosphorus. The halide partner now varies in the given set of compounds. Electronegativity drops as you move down the group from fluorine to iodine. The electrons become diffuse in the space around the nucleus of each atom as the size of the atom increases. As the electrons in the outermost shell are sheltered by electrons in the inner shells, their electron pull diminishes.

The shared pair of electrons between phosphorus and halogen will reside on phosphorus more in iodine than fluorine when the electronegativity declines from fluorine to iodine.

The lone pair-bond pair repulsion will be stronger as the electron density of phosphorus increases.The bond angle increases as the repulsion increases.

As a result, PF3 has the lowest bond angle while PI3 has the largest bond angle

PF3 has the lowest bond angle while PI3 has the largest bond angle.