S ECTION 2: M ETALS, N ONMETALS, AND M ETALLOIDS Chapter 19: Elements and their Properties

L EARNING G OALS Describe the properties of typical metals, nonmetals, and metalloids.

P ROPERTIES OF M ETALS 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)

P ROPERTIES OF M ETALS Malleable: they can be hammered or rolled into sheets Ductile: they can be drawn into wires

P ROPERTIES OF M ETALS The atoms of metals generally have 1- 3 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.

P ROPERTIES OF M ETALS 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.

P ROPERTIES OF N ONMETALS 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.

P ROPERTIES OF N ONMETALS 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.

P ROPERTIES OF N ONMETALS 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. H 2 N 2, O 2, F 2, Cl 2, Br 2, I 2

P ROPERTIES OF M ETALLOIDS 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.

P ROPERTIES OF M ETALLOIDS Metalloids can also be called semiconductors: Semiconductors: elements than conduct an electric current under certain conditions.