Since the same elements make up coal and diamonds, which of the following best explains why they have different properties?

• A. Coal contains more hydrogen than diamonds.
• B. Coal and diamonds have different numbers of protons in their atoms.
• C. Diamonds are a mixture, while coal is a pure substance.
• D. They have different arrangements of carbon atoms.

Answer: (D)

Verified step by step guidance

1. Understand that both coal and diamonds are primarily composed of carbon atoms, meaning they have the same element but different structures.
2. Recall that the properties of a substance depend not only on the types of atoms present but also on how these atoms are arranged and bonded together.
3. Recognize that coal has a more disordered, amorphous structure with carbon atoms bonded irregularly and contains impurities like hydrogen, while diamonds have a highly ordered, crystalline structure where each carbon atom is tetrahedrally bonded to four other carbon atoms.
4. Note that the number of protons in the atoms does not change because both substances are made of carbon atoms, so this cannot explain the difference in properties.
5. Conclude that the key reason for the different properties of coal and diamonds is the different arrangement (or bonding pattern) of carbon atoms, which affects hardness, conductivity, and other physical characteristics.