4.3 FAMILIES OF ELEMENTS I can: -recognize the periodic table was made by placing elements with similar physical and chemical properties in the appropriate groups or families. -recognize that association with group or family is based on similar chemical or physical properties -determine if an element is a metal or nonmetal based on its position on the periodic table and associate specific properties with those positions -distinguish that an element is a metalloid and has some properties of metals and nonmetals. R -identify the specific families for metals, nonmetals, metalloids, periods and groups or families and associate families with the type of element (metal, nonmetal, metalloid)

HOW ARE ELEMENTS CLASSIFIED?  3 groups  Metals: elements that are shiny and conducts heat and electricity well.  Nonmetals: an element conducts heat and electricity poorly  Could be solid, liquid or gas.  Solids=brittle  Semiconductors: element that conducts electric current better than insulator, but not as well as conductor.  Still considered nonmetal.

METALS  Alkali metal: group 1  Soft, shiny, react violently with water.  One valence electron  Some are so reactive, they are only found as compounds.  Alkaline-earth metals: group 2  Two valence electrons (typically form compounds)  Ca: Coral, limestone, marble  Mg: lightest metal (planes), medicines.

METALS, CONT.  Transition metals: Groups 3-12  Much less reactive  Still conducts heat and electricity  Can obtain a variety of different charges.  Easily shaped (copper, iron, gold silver)

SYNTHETIC ELEMENTS  Technetium and promethium are man-made.  Both radioactive= nucleui continually decaying to make different elements.  Promethium: glow in the dark paints

NONMETALS  Some elements in groups (except for H)  Halogens: Group 17  Chlorine (Cl 2 ) is a poisonous gas, but when combine with Ca, can be used to kill bacteria in pools and drinking water.  Fluorine: poisonous gas, but F - is used in toothpaste and prevents took decay.  NaCl  Noble Gases: Group 18  Unreactive because p and s orbitals are full of electrons.

SEMICONDUCTORS (6 METALLOIDS)  Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium  Non metals that share a few properties with metals.  Boron added to steel to increase strength at high temperatures. 