Evaluating Statements on C, N, S Elements

Steps:

• Statement 1: Carbon (group 14), nitrogen (group 15), sulfur (group 16) occupy consecutive groups in the periodic table.
• Statement 2: Common isotopes show ratios of 1:1—C-12 (6n/6p), N-14 (7n/7p), S-32 (16n/16p)—not 2:1.
• Statement 3: Each forms acidic oxides—CO₂ dissolves in water to form H₂CO₃, NO₂ forms HNO₃/HNO₂, SO₂ forms H₂SO₃.
• Correct statements are 1 and 3, so option C.

Why C is correct:

• Groups 14–16 are adjacent per periodic table structure, and nonmetal oxides like CO₂, NO₂, SO₂ react with water to form acids (Bronsted-Lowry definition).

Why the others are wrong:

• A: Includes false statement 2 on neutron-proton ratios.
• B: Includes false statement 2 and excludes true statement 3.
• D: Includes false statement 2 and excludes true statement 1.

Final answer: C