What is the basic unit of all matter?

The basic unit of all matter is the atom. Atoms are the smallest units that maintain the properties of an element and are composed of subatomic particles: protons, neutrons, and electrons. They serve as the fundamental building blocks for all substances in the universe.

Molecules, on the other hand, are formed when two or more atoms bond together. While they are essential for understanding chemical structures and compounds, they are not the simplest unit of matter.

Elements refer to pure substances that consist of only one type of atom. For instance, oxygen is an element because it is made up solely of oxygen atoms. Compounds are substances formed when two or more different types of atoms chemically bond together, like water (H2O), which contains hydrogen and oxygen atoms.

In summary, while molecules, compounds, and elements play significant roles in chemistry and the composition of matter, the atom stands as the most fundamental unit.