Element:A pure substance that cannot be broken down into simpler substances by chemical means. It is the fundamental building block of matter, consisting of atoms with the same atomic number.
Atom: The smallest unit of an element that retains its chemical properties. Atoms are composed of protons, neutrons, and electrons, and their arrangement and number determine the element's properties.
Atomic Number:The number of protons in the nucleus of an atom, which is unique for each element and determines its chemical properties.