Which of the following best represents the Lewis dot structure for the neutral compound CH_4 (methane)?

• A. A central C atom with four single bonds to four H atoms, and no lone pairs on C.
• B. A central C atom with one triple bond to one H atom, and three single bonds to three H atoms.
• C. A central C atom with four single bonds to four H atoms, and two lone pairs on C.
• D. A central C atom with two double bonds to two H atoms, and two lone pairs on C.

Answer: (A)

Verified step by step guidance

1. Step 1: Identify the total number of valence electrons in the molecule. Carbon (C) has 4 valence electrons, and each hydrogen (H) has 1 valence electron. Since there are 4 hydrogens, total valence electrons = 4 (from C) + 4 × 1 (from H) = 8 electrons.
2. Step 2: Determine the bonding pattern. Carbon typically forms 4 bonds to complete its octet, and hydrogen forms only 1 bond to fill its duet. So, expect carbon to form four single bonds with four hydrogen atoms.
3. Step 3: Draw the Lewis structure with carbon in the center and four single bonds connecting it to each hydrogen atom. This uses 8 electrons (4 bonds × 2 electrons per bond), which accounts for all valence electrons.
4. Step 4: Check for lone pairs. Since all valence electrons are used in bonding, carbon has no lone pairs, and each hydrogen has none as well.
5. Step 5: Confirm that the octet rule is satisfied for carbon (8 electrons around it) and the duet rule for hydrogen (2 electrons around each). This confirms the correct Lewis structure is a central carbon atom with four single bonds to four hydrogen atoms and no lone pairs on carbon.