Question

Draw a Lewis structure for (a)${\mathbf{PF}}_3$; (b)${\mathbf{H}}_2{\mathbf{CO}}_3$(both H atoms are attached to O atoms); (c)${\mathbf{CS}}_2$.

Short answer

The Lewis structure of

a.

b.

c.

Step-by-step solution

Lewis Structure

A Lewis structure can be defined as the basic structure of a molecule which used the valence electron of each atom involved. In Lewis’s structure, the least electronegative atom will be the central atom.

Part (a) Explanation 

In this molecule, the phosphorus has 5 electrons in the valence orbital which can bond to the 3 F-atoms and form three single bonds. There are remaining two electrons on P-atom which form a lone pair around the molecule and one electron is given by all 3 F-atom in order to fulfil the octet of each other.

${\mathbf{PF}}_3$is a Tetrahedral structure.

Part (b) Explanation

C belongs the group 14 having 4 electrons in the valence shell and requires 4 electrons, O-atom belongs togroup 16 having 6 electrons in the valence shell and requires 2 electrons to fulfil the octet and H belongs to group 1 having 1 electron in the valence shell requires 1 electron to fulfil the duplet. The 2 electrons required will be provided by 2 H to O-atom and 4 electrons from other 3 O-atom.

${\mathrm{H}}_2{\mathrm{CO}}_3$is Trigonal Planar.

Part (c) Explanation

In this molecule, the C-atom has 4 electrons in the valence orbital and requires 4 more electrons to fulfil the octet which is given by the S-atom and forms an unsaturated molecule having a double bond. The S-atom also require 2 electrons to fulfil its octet which is given by the C-atom.

${\mathrm{CS}}_2$is a Linear structure.