Chapter 4, Problem 4.29UKC

(a)

Interpretation Introduction

Interpretation:

The molecular formula of thalidomide is to be determined.

Concept introduction:

Molecular formula of a compound indicates the numbers of all the elements present in a molecule.

(b)

Interpretation Introduction

Interpretation:

The positions of all multiple bonds in the given structure of thalidomide are to be shown.

Concept introduction:

Covalent bonds are formed by sharing of electrons between atoms.

The valence electrons of Carbon are 4 electrons (requires 4 electrons to achieve octet).

The valence electrons of Oxygen are 6 electrons (requires 2 electrons to achieve octet).

The valence electrons of Hydrogen are 1 electron.

The valence electrons of Nitrogen are 5 electrons (requires 3 electrons to achieve octet).

The sharing of one electron from two atoms constitutes a single bond between the two atoms. The sharing of two electrons from two atoms constitutes a double bond between the two atoms.

(c)

Interpretation Introduction

Interpretation:

The geometry around the each carbon atoms and nitrogen atom of the thalidomide are needed to be determined.

Concept introduction:

Molecular geometry can be predicted from the structure by using the valence-shell Electron-pair repulsion (VSEPR) model.

-Count the number of valence electron pairs (bond pairs and lone pairs).

-Assume that the valence electron pairs form a structure that allows them to be as far away from each other as possible.

-If there are only two bond pair electrons, the molecule is linear.

-If there are three bond pair electrons, the molecule is shaped like a trigonal planar.

-If there are four bond pair electrons, the molecule is shaped as a regular tetrahedral.

- Repulsion between lone pair-bond pair of electrons effect the geometry of molecules.