What is a molecule?

A molecule is defined as a group of two or more atoms that are bonded together, representing the smallest fundamental unit of a chemical compound that retains the chemical properties of that compound. This concept is important in understanding the nature of substances in chemistry.

When considering the correct choice, the characterization of a molecule as "the smallest part of a substance that is not an element" emphasizes that a molecule consists of various types of atoms bonded together, forming compounds. Unlike elements, which consist of single types of atoms, molecules can be made up of different elements. For example, water (H₂O) is a molecule composed of hydrogen and oxygen atoms.

The other options suggest different meanings that do not accurately define a molecule. While one might consider the smallest part of an element, that would refer to an atom itself. Similarly, the description of a molecule as the smallest part of a compound is not comprehensive, as it does not clarify that molecules can be formed by different types of atoms. Finally, referring to a molecule as merely "a larger group of atoms bonded together" can be ambiguous. It overlooks the fundamental point that the bonding and arrangement of specific atoms result in distinct chemical and physical properties, which define the identity of the molecule.

In summary, acknowledging