Evaluating statements on allotropes and silicon(IV) oxide structures

Steps:

• Statement 1 is correct: Both diamond and SiO2 have giant covalent lattices with tetrahedral bonding, making them hard.
• Statement 2 is correct: SiO2 forms a 3D network of alternating Si and O atoms bonded covalently.
• Statement 3 is correct: Diamond's structure features each carbon atom tetrahedrally bonded to four others.
• Statement 4 is incorrect: Diamond does not conduct electricity due to localized electrons; only graphite does via delocalized electrons.

Why A is correct:

• A selects statements 1, 2, and 3, which accurately describe the hardness from similar giant structures, SiO2's lattice, and diamond's tetrahedral bonding per covalent network theory.

Why the others are wrong:

• B includes false statement 4 on conductivity.
• C includes false statement 4 on conductivity.
• D includes false statement 4 on conductivity.

Final answer: A