Which of the following best describes how molecules differ from atoms?

• A. Molecules contain only protons and neutrons, while atoms contain electrons as well.
• B. Molecules are always electrically charged, while atoms are always neutral.
• C. Molecules are composed of two or more atoms chemically bonded together, while atoms are single units of elements.
• D. Atoms can only exist as part of molecules and never independently.

Answer: (C)

Verified step by step guidance

1. Understand the difference between atoms and molecules: Atoms are the smallest units of an element that retain the chemical properties of that element. Molecules, on the other hand, are formed when two or more atoms chemically bond together.
2. Clarify the composition of atoms: Atoms consist of protons, neutrons, and electrons. Protons and neutrons are located in the nucleus, while electrons orbit the nucleus.
3. Clarify the composition of molecules: Molecules are made up of two or more atoms that are chemically bonded. These atoms can be of the same element (e.g., O₂) or different elements (e.g., H₂O).
4. Address the incorrect statements: Molecules are not always electrically charged; they can be neutral. Atoms can exist independently (e.g., noble gases like helium), so the statement that atoms can only exist as part of molecules is incorrect.
5. Conclude with the correct description: Molecules are composed of two or more atoms chemically bonded together, while atoms are single units of elements. This is the most accurate description of how molecules differ from atoms.