The Periodic Table of Elements Dmitri Mendeleev published the first periodic table in 1869 Made it possible for scientists to predict the existence of elements that had not been discovered yet http://www.youtube.com/watch?v=zUDDiWtFtEM periodic table song

Organization Periodic means- happening at regular intervals Arranged in increasing atomic mass and atomic number Periods are the horizontal rows of elements Same number of energy levels for electrons Groups or families are the vertical column of elements Share chemical properties Same # of valence electrons

Groups are vertical Periods are horizontal

Periodic Law The repeating chemical and physical properties of elements change periodically with the element atomic number

Metals, Nonmetals, & Metalloids Most elements are metals Found to the left of the zigzag line Properties: malleable or ductile, good electric & thermal conductors

Nonmetals Found to the right of the zigzag line Properties: malleable or ductile

Metalloids Border the zigzag line Properties of metals and nonmetals Properties: shiny, brittle, hard, good conductors of electric current

Groups Alkali metals- found in group 1 of the periodic table Contains metals Electrons in outer energy level 1 Electrons in the out level (VE) 1 Very reactive Properties: soft, silver in color, shiny, low density

Alkaline-Earth Metals- found in group 2 of the periodic table Contains metals Electrons in outer level (VE) 2 Very reactive, but less than alkali metals Properties: silver in color, higher density than alkali metals

Transition Metals- found in groups 3-12 of the periodic table Contains metals Electrons in the outer energy level (VE) 1 or 2 Less reactive than alkaline earth metal group Properties: shiny, good conductors of thermal energy & electric current, higher densities and melting points of groups 1 and 2

Halogens- found in group 17 of the periodic table Contains nonmetals Electrons in the outer energy level (VE) 7 Very reactive Properties: poor conductors of electric current, violent reactions with alkali metals to form salts, never in pure form in nature

Nobel Gases- found in group 18 of the periodic table Contains nonmetals Electrons in the outer energy level (VE) 8 Nonreactive Properties: colorless, odorless, gases at room temperature

Vocabulary Make index cards for the following terms for homework. Periodic alkali metal Period alkaline-earth metal Group halogen Periodic law noble gas Valence electron