Chapter 12, Problem 51A

Interpretation Introduction

Interpretation:

The molecular structure of given molecule is to be predicted and bond angle is to written.

Concept introduction:

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

Answer to Problem 51A

The molecular structure of $\mathrm{C}{\mathrm{O}}_3{}^{2-}$ is trigonal planar.

The $\mathrm{O}-\mathrm{C}-\mathrm{O}$ bond angle is $120°$

Explanation of Solution

Lewis structure of $\mathrm{C}{\mathrm{O}}_3{}^{2-}$ is:

  

It shows, there are 3 bond pairs and no lone pairs around carbon atom. Therefore, by VSEPR theory its shape is trigonal planar. Therefore, the $\mathrm{O}-\mathrm{C}-\mathrm{O}$ bond angle is $120°$

Conclusion

Thus, carbonate ion is flat with bond angle $120°$