Chapter 12, Problem 44A

Interpretation Introduction

Interpretation:

The principles that determine the molecular structure of a molecule are to be written.

Concept introduction:

Molecular structure represents the arrangement of atoms in a molecule.

This arrangement can be predicted using VSEPR theory.

Answer to Problem 44A

The principles that determine the molecular structure of a molecule are:

• Lewis structure of a molecule is drawn.
• Two electron pairs around the central atom form the linear geometry.
• Three electron pairs around the central atom form the trigonal planar geometry.
• Four electron pairs around the central atom form the tetrahedral geometry.
• Presence of lone pairs around central atom distorts the geometry and shape of molecule is changed accordingly.
• Double bond and triple bond are also counted one repulsive unit and gives the same effect as single bond.

Explanation of Solution

VSEPR theory helps to draw the molecular shape as:

Total number of valence electron pairs	Number of bond pairs	Number of lone pairs	Geometry and shape
2	2	0	linear
3	3	0	Trigonal planar
	2	1	bent
4	4	0	Tetrahedral
	3	1	Pyramidal
	2	2	Bent

Conclusion

Thus, to draw the shape of molecules, Lewis dot structures and VSEPR theory is helpful.