What is the smallest part of an element that can exist?

The smallest part of an element that can exist independently is an atom. Atoms are the fundamental building blocks of matter and represent the basic units of chemical elements. Each element on the periodic table is made up of atoms, which consist of a nucleus containing protons and neutrons, surrounded by electrons in energy levels.

Molecules, on the other hand, are formed when two or more atoms bond together. While they can consist of atoms of the same element or different elements, they are not the smallest units of the elements themselves. Compounds are substances formed from two or more different elements bonded together, which means they are also larger than atoms. Solutions involve mixtures of substances and are not tied to the concept of the smallest unit of an element.

Thus, choosing atoms as the answer correctly identifies them as the simplest unit of an element that retains its chemical properties.