Which of the following statements correctly describes elements?

• A. Elements are always composed of molecules containing different types of atoms.
• B. Elements are pure substances that cannot be broken down into simpler substances by chemical means.
• C. Elements can be separated into their components by physical processes.
• D. Elements are mixtures of two or more substances.

Answer: (B)

Verified step by step guidance

1. Understand the definition of an element: An element is a pure substance consisting of only one type of atom, and it cannot be broken down into simpler substances by chemical means.
2. Analyze the first statement: 'Elements are always composed of molecules containing different types of atoms.' This is incorrect because elements consist of only one type of atom, not different types.
3. Evaluate the second statement: 'Elements are pure substances that cannot be broken down into simpler substances by chemical means.' This aligns perfectly with the definition of an element.
4. Consider the third statement: 'Elements can be separated into their components by physical processes.' This is false because elements are pure substances and cannot be separated into simpler substances by physical means.
5. Review the fourth statement: 'Elements are mixtures of two or more substances.' This is incorrect because elements are pure substances, not mixtures.