Which of the following correctly represents the Lewis dot structure for a neutral molecule of HCl?

• A. H : Cl with three lone pairs on Cl
• B. H : Cl with two lone pairs on Cl
• C. H : Cl with four lone pairs on Cl
• D. H : Cl with no lone pairs on Cl

Answer: (A)

Verified step by step guidance

1. Step 1: Identify the total number of valence electrons in the molecule. Hydrogen (H) has 1 valence electron, and chlorine (Cl) has 7 valence electrons, so the total is 1 + 7 = 8 valence electrons.
2. Step 2: Determine how the atoms are bonded. Since HCl is a diatomic molecule, hydrogen and chlorine are connected by a single covalent bond, which consists of 2 shared electrons.
3. Step 3: Assign the bonding electrons between H and Cl. The single bond accounts for 2 electrons, so subtract these from the total valence electrons: 8 - 2 = 6 electrons remaining.
4. Step 4: Distribute the remaining 6 electrons as lone pairs on the chlorine atom. Since each lone pair consists of 2 electrons, chlorine will have 3 lone pairs (6 electrons) around it.
5. Step 5: Verify the Lewis structure. Hydrogen has 2 electrons around it (satisfying its duet rule), and chlorine has 8 electrons total (2 bonding + 6 lone electrons), satisfying the octet rule. Therefore, the correct Lewis structure is H bonded to Cl with three lone pairs on Cl.