Q10.36P - Chemistry: Molecular Nature Of Matter And Change

Question

Determine the electron-group arrangement, molecular shape, and ideal bond angle(s) for each of the following:

(a)  ${\mathbf{CO}}_3^{2-}$

(b)  ${\mathbf{SO}}_2$

(c)  ${\mathbf{CF}}_4$

Step-by-Step Solution

Answer

The shapes and bond angles of molecules can be determined from the VSEPR theory. The deviations arise mainly due to lone pair-lone pair repulsions. 

Step 1: CO 3 2 - CO 3 2 -

The structure of the molecule would be trigonal planar around the central atom carbon. Ideal bond angle would be${\mathbf{120}}^0$

Step 2: SO 2

The sulphur atom is sp³ hybridised. The expected structure of the molecule would be trigonal planar around the central atom sulphur. Ideal bond angle would be ${\mathbf{120}}^0$. However, the lone pairs around the sulphur atom reduces the bond angle from ${\mathbf{120}}^0$. Then the shape can be considered bent.

Step 3: CF 4

The shape of ${\mathbf{CF}}_4$ is tetrahedral. The expected bond angle is $\mathbf{109}\mathbf{.}{\mathbf{5}}^0$.