What is the smallest unit of matter that retains the properties of an element?

The smallest unit of matter that retains the properties of an element is an atom. Atoms are the basic building blocks of all matter and are composed of protons, neutrons, and electrons. Each element is defined by the number of protons in its nucleus, which determines its identity and properties. For instance, an atom of carbon will always have six protons, and this unique arrangement of subatomic particles gives carbon its characteristic chemical behavior.

Molecules and compounds, while they are indeed forms of matter, are made up of two or more atoms bonded together. Molecules are formed from the same element or different elements, and compounds specifically refer to molecules composed of different elements. In both cases, the properties of the resulting substance can be different from those of the individual elements that compose them.

Cells are the structural and functional units of living organisms and are much larger and more complex than atoms. Cells comprise various molecules, including proteins, lipids, carbohydrates, and nucleic acids, which are themselves made up of atoms.

Thus, an atom is the fundamental unit that maintains the specific properties associated with each element, setting it apart from molecules, compounds, and cells.