SECTION 2: METALS, NONMETALS, AND METALLOIDS Chapter 19: Elements and their Properties LEARNING GOALS Describe the properties of typical metals, nonmetals, and metalloids. PROPERTIES OF METALS Metals can be found to the left of the “staircase” on the periodic table. Almost all solid Mercury (Hg) is the exception! Good conductors of heat and electricity They reflect light (shiny, luster) PROPERTIES OF METALS Malleable: they can be hammered or rolled into sheets Ductile: they can be drawn into wires PROPERTIES OF METALS The atoms of metals generally have 13 valence electrons. In chemical reactions, metals tend to give up electrons easily. When metals combine with nonmetals, the atoms tend to lose electrons to the atoms of nonmetals, forming ionic bonds. PROPERTIES OF METALS Metallic bonding: positively charged metallic ions are surrounded by a cloud of electrons. The outer-level electrons are not tightly held to the nucleus and can move freely among the charged ions. PROPERTIES OF NONMETALS Nonmetals: elements that usually are gases or brittle solids at room temperature. The solids break easily (brittle) and are not malleable or ductile. Most nonmetals do not conduct heat or electricity well and are not shiny. PROPERTIES OF NONMETALS The electrons of nonmetals are strongly attracted to the nucleus of the atom. They can form ionic bonds, in which they gain electrons from metals. They can also form covalent bonds, in which they share electrons with other nonmetals. PROPERTIES OF NONMETALS About 90% of all atoms in the universe are hydrogen atoms! Hydrogen is a diatomic molecule: Consists of two atoms of the same element in a covalent bond. H2 N2, O2, F2, Cl2, Br2, I2 PROPERTIES OF METALLOIDS Metalloids can form ionic and covalent bonds with other elements and can have both metallic and nonmetallic properties. Some metalloids can conduct electricity better than most nonmetals, but not as well as metals. PROPERTIES OF METALLOIDS Metalloids can also be called semiconductors: Semiconductors: elements than conduct an electric current under certain conditions.