All of the hydrogens are bonded to carbon in both of the following. Write a Lewis formula...

All of the hydrogens are bonded to carbon in both of the following. Write a Lewis formula that satisfies the octet rule for each.

(a) Formaldehyde (CH₂O)

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(b) Hydrogen cyanide (HCN)

Sample Solution (a) Formaldehyde has 12 valence electrons; 4 from carbon, 2 from two hydrogens, and 6 from oxygen. Connect carbon to oxygen and both hydrogens by covalent bonds.

Pair the unpaired electron on carbon with the unpaired electron on oxygen to give a carbon-oxygen double bond. The resulting structural formula satisfies the octet rule.