Which property of $C$ best explains its ability to form large and complex structures in organic molecules?

• A. $C$ atoms are always found in ionic compounds, which leads to complex structures.
• B. $C$ can only form double bonds, limiting its structural diversity.
• C. $C$ can form $4$ covalent bonds, allowing it to create diverse and stable structures.
• D. $C$ has a high electronegativity, making it highly reactive with metals.

Answer: (C)

Verified step by step guidance

1. Understand that the question asks which property of carbon (C) explains its ability to form large and complex organic structures.
2. Recall that carbon has four valence electrons, allowing it to form up to four covalent bonds with other atoms, which is key to building complex molecules.
3. Recognize that carbon typically forms covalent bonds rather than ionic bonds, so the statement about carbon atoms always being in ionic compounds is incorrect.
4. Note that carbon can form single, double, and triple bonds, not just double bonds, which contributes to structural diversity.
5. Understand that carbon's electronegativity is moderate, enabling stable covalent bonding rather than high reactivity with metals, so this property does not primarily explain its structural complexity.