Question

1. what is the vsepr molecular shape of ph₃? support your answer with a lewis structure below.

trigonal planar color blue
tetrahedral color yellow
pyramidal color green

1. tw lo

Explanation:

Step1: Determine the number of valence electrons

Phosphorus (\(P\)) has \(5\) valence electrons and each hydrogen (\(H\)) has \(1\) valence electron. For \(PH_{3}\), the total number of valence electrons is \(5+(3\times1)=8\).

Step2: Draw the Lewis structure

The central atom is \(P\). Each \(H\) is bonded to \(P\) with a single bond. After forming three \(P - H\) bonds (using \(3\times2 = 6\) electrons), there is one lone pair (\(2\) electrons) on \(P\). So the Lewis structure has \(P\) in the center with three \(H\) atoms bonded to it and one lone pair on \(P\).

Step3: Apply VSEPR theory

According to VSEPR, the electron - pair geometry is tetrahedral (because there are \(4\) electron - pairs: \(3\) bonding pairs and \(1\) lone pair). But the molecular shape (which considers only the positions of atoms) is pyramidal. The lone pair exerts a stronger repulsion than bonding pairs, pushing the \(P - H\) bonds downwards.

Answer:

The VSEPR molecular shape of \(PH_{3}\) is pyramidal.