Periodic Table Properties

Alkali Metals (GROUP 1/1A)

• Less dense than other metals

• One loosely bound valence electron

• Highly reactive, with reactivity increasing moving down the group

• The largest atomic radius of elements in their period

• Low ionization energy

• Low electronegativity

Alkaline Earth Metals (GROUP 2/2A)

• Two electrons in the valence shell

• Readily form divalent cations

• Low electron affinity

• Low electronegativity

Transition Metals (GROUP 3-12/1-10B)

• Very hard, usually shiny, ductile, and malleable

• High melting and boiling points

• High thermal and electrical conductivity

• Form cations (positive oxidation states)

• Tend to exhibit more than one oxidation state

• Low ionization energy

Metalloids or Semimetals

• Electronegativity and ionization energy intermediate between that of metals and nonmetals

• May possess a metallic luster

• Variable density, hardness, conductivity, and other properties

• Often make good semiconductors

• Reactivity depends on the nature of other elements in the reaction

Nonmetals

• High ionization energy

• High electronegativity

• Poor electrical and thermal conductors

• Form brittle solids

• Little if any metallic luster

• Readily gain electrons

Halogens

• Extremely high electronegativity

• Very reactive

• Seven valence electrons, so elements from this group typically exhibit a -1 oxidation state

Noble Gases

have complete valence electron shells, so they act differently. Unlike other groups, this group is unreactive and have very low electronegativity or electron affinity.