The chemical elements are the basic building blocks of matter (atoms) in the universe as we know it. Simply speaking, matter assumes three basic forms: liquid, solid, and gas, and every substance that exists is comprised of one or more atoms, joined together in a cohesive bond. When these elements are joined together, they form certain compounds, assume certain basic shapes, and exhibit certain basic characteristics.
Some elements, such as the gases, cannot be seen with the naked eye, but their presence can still be felt. Some elements are radioactive and give off energy. Still others are brilliant and beautiful (i.e. crystals, gems, and precious metals)! All are important and serve definite purposes, even to the sustaining of life!
There are 118 known chemical elements, and scientists have classified them on what is know as The Periodic Table. These elements are arranged by atomic number, which is determined by the number of protons (positively-charged particles) existing in the atom's nucleus, and by certain properties, behaviors, and characteristics.