What is a Metal? EQ: Is there a better way to organize the elements on the periodic table? Purpose: Examine physical and chemical properties of elements. Determine properties used to classify elements on the periodic table. Expert Information The periodic table is divided into three major groups: metals, nonmetals, and metalloids. The metals are on the left-hand side of the periodic table and the nonmetals are on the right. There is a special type of nonmetal called noble gases located in group 18. They are called noble gases because their outer energy level is full with 8 valence electrons which makes them stable and unlikely to react with other elements. A zigzag or stair-step line separates the metals and nonmetals. Metalloids are adjacent to either side of the stair-step line, except Aluminum, which is a metal. Metalloids include Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium, and Astatine. Octet Rule Atoms combine, or bond, when the positive charge of the proton in the nucleus in one atom is attracted to the negative electrons of another atom. Since metals have fewer valence electrons, the attraction between the nucleus and the valence electrons is weaker so the valence electrons float around the metals instead of being completely attached. This is the controlling factor for the Octet Rule, which states that elements bond in order to have 0 or 8 valence electrons. In other words, elements bond to be more stable. Metals become more stable by getting rid of valence electrons to get to 0 valence electrons, while nonmetals steal or share electrons to get to 8 valence electrons. Valence electrons are the controlling factors for physical and chemical properties of the atoms as listed in the “Properties of Metals and Nonmetals” table. Properties of Metals and Nonmetals Property Metals Nonmetals Reason Conductivity Electricity needs freely moving electrons to be conducted. Heat is the vibration of the atom. The freely moving electrons allow the heat to be passed at a more rapid rate. Luster (shiny or dull) The freely moving electrons reflect all the wavelengths of light. The reflection of all the light makes metals appear shiny. Color The freely moving electrons reflect all the wavelengths of light. The reflection of all the light makes metals appear Silver or Gray Strength (malleable or brittle) The freely moving electrons allow metals to bend instead of break. Reactivity Acids want extra electrons. Metals electrons float freely around, and are easy to steal The freely moving electrons around the nucleus are easy to steal. Magnetism Scientists are still not sure how magnetism works. They do know that it involves freely moving electrons, which metals have.