Section 20-1 Metals The periodic table divides the elements into three classes: metals, nonmetals, and metalloids. Metals are found to the left of the zigzag or stairstep line.

Physical properties of metals: 1. Good conductors of heat and electricity 2. All but one is a solid at room temperature 3. They are shiny because they reflect light. This is called luster.

Physical properties of metals: cont’d 4. They are malleable which means they can be hammered into thin sheets 5. They are ductile, meaning they can be drawn into wires

Chemical properties of metals: 1. They generally have from 1 to 3 electrons in their outer energy level. In chemical reactions they tend to lose these electrons easily and form positive ions.

Chemical properties of metals: cont’d 2. When metals combine with nonmetals the metals tend to lose their outer electrons to the nonmetals forming ionic bonds 3. Metal atoms bond to other metal atoms by metallic bonds in which positive metallic ions are surrounded by a cloud of electrons. The loosely held outer level electrons can move freely from one atom to another.

4. Metallic bonding explains some of the properties of metals. When a metal is hammered or drawn into a wire, it does not break because the positive ions are in layers that slide past each other without losing their attraction to the electron cloud. 5. Metals are good conductors of electricity because of their weakly held outer-level electrons.

Families and Groups

Alkali Metals – elements in Group1 or IA Properties: 1. softer than most other metals 2. most reactive of all the metals 3. react violently with oxygen and water 4. don’t occur in nature in elemental form 5. are stored under oil to prevent reactions Atoms of alkali metals have 1 electron in their outer energy levels which is given up when they combine with other elements. As a result they form positive ions in compounds such as sodium chloride or potassium bromide.

Alkaline Earth Metals – elements in Group 2 or IIA Properties: 1. Very reactive but not as reactive as the alkali metals 2. Not found as free elements in nature 3. Have two valence electrons in outer energy level, which they give up when they combine with a nonmetal 4. They form positive 2 ions 5. Include beryllium, magnesium, calcium, strontium, barium, and radium

Transition elements – elements in groups 3 through 12 in periodic table Includes the most familiar metals such as iron, copper, nickel, silver, gold, zinc, and mercury Transition metals often form colored compounds. Rubies and emeralds are red and green because of the metal chromium. There are paints called cadmium yellow and cobalt blue. Copper compounds are green or blue. Iron oxide is red (rust). Transition Elements

Iron is the main component of steel. It is the second most abundant metallic element in Earth’s crust after aluminum. Copper, gold, and silver can be found free in nature and gold and silver were once used to make coins.

Transition elements cont’d Copper is used in electrical wiring because it is one of the best conductors of electricity. Mercury is the only metal that is liquid at room temperature and is used in thermometers, thermostats, and switches.

Zinc, cadmium, and mercury are found in group 12. Zinc combines with air to form a thin, protective coating of zinc oxide on its surface. Zinc is used to coat other metals to prevent corrosion (such as galvanized buckets and nails). Silver iodide and silver bromide are used to make photographic film and paper.

The Inner Transition Metals the two rows of elements at the bottom of the periodic table. These were taken out of the table so it would not be so wide and could fit on one sheet of paper. They are actually part of periods 6 and 7.

Inner Transition Metals cont’d The first row of the inner transition metals is called the Lanthanide series. The second row is called the Actinide series. The Lanthanides – elements 58 to 71 that follow the element Lanthanum. The Actinides – elements 90 to 103 that follow the element Actinium. All of the actinides are radioactive and unstable. Uranium is the heaviest element that is found in the earth’s crust. Elements after uranium are man made elements