Which of the following best describes an element?

• A. A substance that cannot be broken down into simpler substances by chemical means.
• B. A compound formed by the combination of two elements.
• C. A mixture of two or more compounds.
• D. A substance composed of atoms of different types.

Answer: (A)

Verified step by step guidance

1. Understand the definition of an element in chemistry: An element is a pure substance consisting entirely of one type of atom.
2. Recall that elements cannot be broken down into simpler substances by chemical means because they are the simplest form of matter with unique properties.
3. Differentiate elements from compounds, which are substances formed by chemically combining two or more different elements.
4. Recognize that mixtures consist of two or more substances (elements or compounds) physically combined, not chemically bonded.
5. Conclude that the best description of an element is: 'A substance that cannot be broken down into simpler substances by chemical means.'