The three necessary things about any substance are the type of atoms that created it, the method by which the atoms are positioned, and the method by which the atoms are fused together (Trefil, J ., & Hazen, R. 2010). The atom is the fundamental structure of chemistry; atoms are made up of the three essential elements, protons, neutrons and electrons (Encyclopedia Britannica. 2011). Protons convey a positive charge and neutrons convey no charge, while electrons convey a negative charge (Encyclopedia Britannica. 2011). The center of the atom is composed of protons and neutrons; together they create the nucleus of the atom. (Encyclopedia Britannica. 2011). The most important attribute of an atom is its atomic number, symbolized by the letter Z (Encyclopedia Britannica. 2011). This attribute is expressed as the number of protons in the nucleus (Encyclopedia Britannica. 2011). If an atom has a Z of 6, it is carbon, while a Z of 92 corresponds to uranium (Encyclopedia Britannica. 2011). In short, the amount of protons in the nucleus governs the chemical properties of an atom (Encyclopedia Britannica. 2011). Orbits describe the chemical properties of different atoms (Encyclopedia Britannica. 2011). All electron orbits have a quantum number n and orbits with the same value of n form a shell (Encyclopedia Britannica. 2011). Hydrogen, lithium and sodium have similar properties with one electron in the outermost shell (Encyclopedia Britannica. 2011). The valence shell which is the outermost shell of electrons controls the chemical actions of an atom (Encyclopedia Britannica. 2011). The amount of electrons in the shell depends on how many remain after all the internal shells are full (Encyclopedia Britannica. 2011)... half of the document... accessed October 10, 2011, from http: //www.nobelprize.org /educational/physics/integrated_circuit/history/Robin. (2010). Artificial Intelligence Overview. Retrieved October 10, 2011, from http://intelligence.worldofcomputing.net/ai-introduction/artificial-intelligence-overview.htmlSchulz, M. (1999). The end of the road for silicon? Macmillan Magazines Ltd. Retrieved October 10, 2011, from http://people.ccmr.cornell.edu/~davidm/David_A_Muller_files/gox-comment.pdfTech Target. (2011). Microchip. Retrieved October 10, 2011, from http://searchcio-midmarket.techtarget.com/definition/microchip Thomas Jefferson National Accelerator Facility - Office of Science Education (n.d.) http://education.jlab.org/atomtour/Trefil, J. , & Hazen, R. (2010). The sciences: an integrated approach (Rev.ed). [EbraryReader version]. Retrieved from https://campus.ctuonline.edu