Which statement best describes how a compound is different from an element?

• A. A compound has a variable composition, while an element has a fixed composition.
• B. A compound consists of two or more different elements chemically bonded together, while an element contains only one type of atom.
• C. A compound can be separated into its components by physical means, while an element cannot.
• D. A compound always exists as a gas at room temperature, while an element is always a solid.

Answer: (B)

Verified step by step guidance

1. Understand the definitions of element and compound: An element is a pure substance consisting of only one type of atom, while a compound is a substance formed when two or more different elements are chemically bonded together.
2. Recognize that elements have a fixed composition because they contain only one kind of atom, whereas compounds have a fixed ratio of different atoms bonded in a specific way.
3. Note that compounds cannot be separated into their constituent elements by physical means; instead, chemical methods are required to break the bonds between atoms.
4. Recall that the physical state (solid, liquid, gas) of a compound or element at room temperature varies widely and is not a defining characteristic that distinguishes compounds from elements.
5. Conclude that the best description differentiates compounds and elements based on their atomic composition and chemical bonding, not on physical state or separability by physical means.