Chapter 12 – The Periodic Table Section 2 – Grouping the Elements (pp. 344 - 351

GROUPS 1 & 2 VERY REACTIVE METALS Group 1 – The Alkali Metals The most reactive metals 1 electron in outer energy level Other shared properties – soft, silver colored; shiny; low density Group 2 – The Alkaline Earth Metals -very reactive, but less reactive than alkali metals 2 electrons in outer energy level Other shared properties – silver colored; more dense than alkali metals

THE TRANSITION METALS Groups 3-12 1 or 2 electrons in outer energy level Less reactive than alkaline earth metals Lanthanides and actinides are included in this group Other shared properties: shiny; good conductors of thermal energy and electric current; higher densities and melting points than elements in Groups 1 & 2

LANTHANIDES They follow the element Lanthanum. Shiny, reactive metals

ACTINIDES They follow the element Actinium All are radioactive. This means they are unstable. Elements listed after Plutonium (element 94) do not occur in nature. They are man made.

GROUP 13 Also known as the Boron Group 3 electrons in the outer energy level Group contains Boron (a metalloid) and 4 metals (Al - aluminum, Ga - gallium, In - indium & Tl- thallium) Reactive Other shared properties: solid at room temperature

GROUP 14 Also known as the Carbon Group 4 electrons in outer energy level Reactivity varies among the elements Group contains 1 nonmetal (carbon), 2 metalloids (Si - silicon & Ge - Germanium) and 3 metals (Sn - tin, Pb - lead and Uuq) Other shared properties: solid at room temperature

GROUP 15 Also known as the Nitrogen Group Have 5 electrons in the outer energy level Reactivity varies among the elements Group contains 2 nonmetals (N - nitrogen & P - phosphorus), 2 metalloids (As- Arsenic & Sb - antimony) & 1 metal (Bi - bismuth) Other shared properties: all but Nitrogen are solid at room temperature

GROUP 16 Also known as the Oxygen Group Have 6 electrons in the outer energy level Very reactive Contains 3 nonmetals (O - oxygen, S - sulfur & Se - selenium), 1 metalloid (Te - tellurium) & 2 metals (Po - polonium & Uuh) Other shared properties: all but Oxygen are solid at room temperature

GROUP 17 Also known as the Halogens Group contains all nonmetals (F - fluorine, Cl - chlorine, Br - bromine, I – iodine & At - astatine) Very reactive There are 7 electrons in the outer energy level Other shared properties: poor conductors of electric current; react violently with alkali metals to form salts; never found uncombined in nature.

GROUP 18 Also known as the Noble Gases Group contains all nonmetals (He - helium, Ne - neon, Ar - argon, Kr - krypton, Xe - xenon, Rn – radon & Uuo) There are 8 electrons in the outer energy level (He only has 2) They are unreactive. Other shared properties: colorless, odorless gases at room temperature

HYDROGEN Stands apart Only 1 electron in the outer energy level Very reactive Other properties: colorless, odorless gas at room temperature; low density; reacts explosively with oxygen.