Periodic Table

Mendeleev – Father of P.T. - Arranged elements by characteristics - Could predict properties of missing elements - Put alike elements in columns - Columns – groups or families (18 of them) Rows – periods (because they repeat) (7) Find the elements Group 5 Period 4 Group 15 Period 5 V Sb

Group Names Group 1 – alkali metals * Soft, reactive, 1+ charge as an ion Group 2 – alkaline earth metals * Harder, less reactive, 2+ charge as an ion Groups 3-12 are the Transition metals * All metals, vary in charge Group 17 – halogens * Reactive, nonmetals, diatomic, 1- charge as an ion Group 18 – noble gas * Unreactive, all gases

metals Make up most of the elements on the P.T. * Everything left of red zigzag line Properties of metals Metallic luster (shiny) Good conductors of heat/electricity Ductile/malleable

nonmetals Located to right of red zigzag line Properties of nonmetals (opposite) Dull Bad conductors Brittle

metalloids Located on either side of the red zigzag line Have properties of both: Shiny but brittle

Trends in P.T. Atomic radius: Increases as you go down a group. Why? Adding more energy levels (rings) Decreases as you go from left to right. Why? More protons in nucleus to pull electrons closer. Symbol colors Black – solids Blue – liquids Red - gases

Ions When an atom either loses or gains electron(s). Number of electrons lost or gained = charge Cation – loses elcetron(s) - becomes positive Anion – gains electron(s) - becomes negative