Atoms – An atom is a fundamental object of matter having a relatively heavy nucleus that is surrounded by a cloud of electrons. The nucleus contains over 99.9% of the total mass of an atom. The electrons can be considered either as a collection of orbiting particles or as a standing wave forms (see electrons).  The electrons establish the chemical properties of an element and have a profound influence on its magnetic properties. The word atom comes from a Greek word meaning uncuttable or indivisible. An atom is classified on the basis of the number of protons and neutrons contained by its nucleus. The number of protons determines the chemical element and the number of neutron determines the isotope of the element. An atom is electrically neutral; if it has a net charge it is no longer an atom but and ion. Every element has at least one isotope that is unstable and suffers radioactive decay.

Further Information on this Topic can be found in the books of R.P.W. Scott by following the listed links