Define "compound"

Define "element"

Define "molecule"

Define "atom"

A compound is a substance formed when two or more chemical elements are chemically bonded together

An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge.

An atom a fundamental piece of matter ... An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atomcalled the nucleus and the electrons fly around above the nucleus in a small cloud.

Compound-two or more chemically combined elements

Element-any substance that cannot be broken down into simpler substances

Molecule-a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Atom-the basic unit of a chemical element