Free elements are elements that exist in their pure form and are not combined with other elements. They can be found on the periodic table.
A compound is when two or more different types of atoms bind together chemically, much like a band formed from different musicians.
A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. It's like one song produced by our band analogy above.
The atomic number represents the number of protons in an atom's nucleus - it's kind of like an artist’s ranking on the charts!