Which of the following statements correctly describes the Lewis dot structure of the ion CHO2^- (formate ion)?

• A. It contains one carbon atom single-bonded to two oxygen atoms, both of which carry a negative charge, and single-bonded to a hydrogen atom.
• B. It contains one carbon atom triple-bonded to one oxygen atom and single-bonded to a hydrogen atom.
• C. It contains one carbon atom double-bonded to two oxygen atoms and single-bonded to a hydrogen atom.
• D. It contains one carbon atom double-bonded to one oxygen atom, single-bonded to another oxygen atom (which carries a negative charge), and single-bonded to a hydrogen atom.

Answer: (D)

Verified step by step guidance

1. Identify the total number of valence electrons for the CHO2^- ion by adding the valence electrons of each atom and including the extra electron due to the negative charge. Carbon has 4 valence electrons, hydrogen has 1, each oxygen has 6, and the negative charge adds 1 more electron.
2. Draw a skeletal structure with carbon as the central atom bonded to the hydrogen atom and the two oxygen atoms. This is because carbon typically forms four bonds and is less electronegative than oxygen.
3. Distribute the electrons to satisfy the octet rule for each atom, starting by placing single bonds between carbon and each attached atom, then adding lone pairs to oxygen atoms to complete their octets.
4. Adjust the bonding by forming a double bond between carbon and one oxygen atom to reduce formal charges and achieve a more stable structure. The other oxygen will remain single-bonded and carry the negative charge, indicated by extra lone pairs.
5. Confirm the final Lewis structure shows carbon double-bonded to one oxygen, single-bonded to another oxygen with a negative charge, and single-bonded to hydrogen, matching the correct description of the formate ion.