ELECTRONS are tiny particles of matter that circle the nucleus in rings called ORBITS. They are kept in their orbits by gravitational fields created by the nucleus. Every type of atom has a different number of electrons in its orbit (e.g. hydrogen has 1, helium has 2 etc.). The way to tell how many electrons an atom has in its orbit is simple; the number of electrons ALWAYS equals the number of protons in the nucleus.
Groups of 2 or more atoms are called MOLECULES. Many molecules (10+) may combine to form a MOLECULAR STRUCTURE. The most basic atom is HYDROGEN. (See periodic table). Atoms with a certain number of protons, neutrons and electrons have enough ATOMIC ENERGY to emit RADIATION, which is harmful to human, plant and animal life.
Some RADIOACTIVE atoms are found in; Uranium, Plutonium, Radon, Americium etc, all of which are ELEMENTS. (See elements).
