Question

Question: Write Lewis structures that obey the octet rule for each of the following. Except for HCN and H₂CO, the first atom listed is the central atom. For HCN and H₂CO, carbon is the central atom.

a. HCN d. NH⁺₄ g. CO₂

b. PH₃ e. H₂CO h. O₂

c. CHCl₃ f. SeF₂ i. HBr

Short answer

Answer

The Lewis structure is the depiction of the outermost orbit electrons in the molecule. The dots are used as valence electrons and a line is used as a bond between the two atoms. Basically, for this representation octet rule is followed.

Step-by-step solution

 Describing the Lewis structure for HCN 

The HCN molecule consists of three atoms H, C and N. The H atom forms a single bond with C, and the C atom forms triple bonds with N. Also, the N atom holds a lone pair.

 Describing the Lewis structure for PH3 

One P and three H atoms are combined to form a PH₃molecule. P has a lone pair which loses for some reactions to act as a nucleophile.

Step 3: Describing the Lewis structure for CHCl3

The chloroform has one carbon, one hydrogen, and three chlorine atoms such as Carbon is the central atom. This molecule has a non-zero dipole moment.

Describing the Lewis structure for NH4+ 

When ammonia is protonated to form an NH₄⁺ion. This ion consists of one N and 4 H atoms withapositive charge on the N atom which shares lone pair with H⁺.

Describing the Lewis structure for H2CO 

H₂CO contains one double bond of C with O and single with H. O atom has two lone pairs. Carbon and Oxygen are sp2 hybridized having a pi bond between them.

Describing the Lewis structure for SeF2 

SeF2 has a total of 8 lone pairs. F has threelone pairs eachand Se has two.

Describing the Lewis structure for CO2 

One carbon atom and two oxygen atoms form CO₂. O has 2 lone pairs for each. C forms double bonds with each.

Describing the Lewis structure for O2 

O₂ has 2 lone pairs for every atom and is attached by a double bond. This molecule show symmetricity around the double bond.

Describing the Lewis structure for HBr

This acid molecule is bonded by a single bond with three lone pairs. The HBr is a strong acid due to a stable conjugate base.