Answer
See the explanation
Work Step by Step
Here are the Lewis structures for the given molecules:
a. $H_{2}CO$:
- The central atom is carbon.
- Carbon has 4 valence electrons, hydrogen has 1 valence electron, and oxygen has 6 valence electrons.
- To satisfy the octet rule, carbon needs to form 4 bonds, hydrogen needs to form 1 bond, and oxygen needs to form 2 bonds.
- The Lewis structure for $H_{2}CO$ is:
${H-C-O-H}$
b. $CO_{2}$:
- The central atom is carbon.
- Carbon has 4 valence electrons, and each oxygen has 6 valence electrons.
- To satisfy the octet rule, carbon needs to form 4 bonds, and each oxygen needs to form 2 bonds.
- The Lewis structure for $CO_{2}$ is:
${O=C=O}$
c. HCN:
- The central atom is carbon.
- Carbon has 4 valence electrons, hydrogen has 1 valence electron, and nitrogen has 5 valence electrons.
- To satisfy the octet rule, carbon needs to form 4 bonds, hydrogen needs to form 1 bond, and nitrogen needs to form 3 bonds.
- The Lewis structure for HCN is:
${H-C≡N}$
In all these molecules, carbon is the central atom, and the Lewis structures are drawn to satisfy the octet rule (duet rule for hydrogen).
