Lewis Dot-and-Cross Diagrams Follow Octet Rule

Steps:

• Count total valence electrons for the compound using atomic numbers.
• Sketch skeletal structure with central atom bonded to others.
• Distribute electrons as lone pairs and shared pairs to satisfy octets.
• Verify all atoms achieve stable electron configurations.

Why A is correct:

• Diagram A shows correct shared and lone pairs, adhering to the octet rule where each atom has 8 valence electrons (except hydrogen with 2).

Why the others are wrong:

• B incorrectly shows unpaired electrons on central atom, violating octet rule.
• C has excessive lone pairs, exceeding total valence electrons available.
• D misplaces bonds, resulting in incomplete octet for oxygen.

Final answer: A