alkali metals, alkaline earth metals, noble gases

noble gases

-Relatively nonreactive due to a full valence shell -all gases at room temp. -Radon is the only gas that is radioactive at normal temperatures -Helium is the lightest gas -Neon is used in making lighted signs and displays. examples: He, Ne, Rn

alkaline earth matals

Many of the physical properties common to metals -harder, denser, stronger than alkali metals -higher melting points than alkali metal -less reactive than alkali, nonetheless too reactive to be found in nature as a free element; examples: Ca, Mg, Be

alkali metals

Many of the physical properties common to metals; 1. less dense; 2. only one valence e-; 3. highly reactive; 4. react most readily with halogens; 5. reactivity increases as you move down the group, 6. react strongly with water; 7. can cut with a knife . examples: Rb, Li, Cs