Chapter 18, Problem 18.42SP

(a)

Interpretation Introduction

Interpretation:

The molecular structure of $H_{2}Se$ has to be predicted.

Concept Introduction:

Valence Shell Electron Pair Repulsion Theory:

The shape or structure of a molecule is determined by the repulsion between the entire electrons present in the valence shell.

Bond pairs and lone pairs in the molecule repel each other therefore the electron clouds stay apart as possible to reduce the repulsion and so to increase the stability.

The amount of repulsion can be ordered as follows,

$\text{LP-LP}\text{>}\text{LP-BP}\text{>}\text{BP-BP}$

In order to determine the shape, the Lewis diagram must be drawn first.

$\begin{array}{cccc}No.ofelectronpairs& Bondpair& Lonepair& Molecularstructure\\ 2& 2& 0& Linear\\ 3& 3& 0& Trigonalplanar\\ 3& 2& 1& Bent\left(Vshaped\right)\\ 4& 4& 0& Tetrahedral\\ 4& 3& 1& Trigonalpyramidal\\ 4& 2& 2& Bent\left(Vshaped\right)\end{array}$

(b)

Interpretation Introduction

Interpretation:

The molecular structure of $As{H}_3$ has to be predicted.

Concept Introduction:

Valence Shell Electron Pair Repulsion Theory:

The shape or structure of a molecule is determined by the repulsion between the entire electrons present in the valence shell.

 Bond pairs and lone pairs in the molecule repel each other therefore the electron clouds stay apart as possible to reduce the repulsion and so to increase the stability.

The amount of repulsion can be ordered as follows,

$\text{LP-LP}\text{>}\text{LP-BP}\text{>}\text{BP-BP}$

In order to determine the shape, the Lewis diagram must be drawn first.

$\begin{array}{cccc}No.ofelectronpairs& Bondpair& Lonepair& Molecularstructure\\ 2& 2& 0& Linear\\ 3& 3& 0& Trigonalplanar\\ 3& 2& 1& Bent\left(Vshaped\right)\\ 4& 4& 0& Tetrahedral\\ 4& 3& 1& Trigonalpyramidal\\ 4& 2& 2& Bent\left(Vshaped\right)\end{array}$

(c)

Interpretation Introduction

Interpretation:

The molecular structure of $Si{H}_4$ has to be predicted.

Concept Introduction:

Valence Shell Electron Pair Repulsion Theory:

The shape or structure of a molecule is determined by the repulsion between the entire electrons present in the valence shell.

 Bond pairs and lone pairs in the molecule repel each other therefore the electron clouds stay apart as possible to reduce the repulsion and so to increase the stability.

The amount of repulsion can be ordered as follows,

$\text{LP-LP}\text{>}\text{LP-BP}\text{>}\text{BP-BP}$

In order to determine the shape, the Lewis diagram must be drawn first.

$\begin{array}{cccc}No.ofelectronpairs& Bondpair& Lonepair& Molecularstructure\\ 2& 2& 0& Linear\\ 3& 3& 0& Trigonalplanar\\ 3& 2& 1& Bent\left(Vshaped\right)\\ 4& 4& 0& Tetrahedral\\ 4& 3& 1& Trigonalpyramidal\\ 4& 2& 2& Bent\left(Vshaped\right)\end{array}$