The Periodic Table Ch. 6

Why is the Periodic Table so important to chemists?

Three Classes of Elements Metals Nonmetals metalloids

Same number of valence electrons Groups Elements in the same group have similar chemical and physical properties Why?? Same number of valence electrons

Families Columns are also grouped into families Families may be one column or several Families have names rather than numbers

Hydrogen A family of its own Diatomic Reactive gas

Always combined with something else in nature Soft metals Alkali Metals Group 1A (No hydrogen) Very reactive metals Always combined with something else in nature Soft metals

Alkaline Earth Metals Group 2A Reactive metals Always combined with nonmetals in nature Some are important mineral nutrients (Mg and Ca)

Less reactive harder metals Transition Metals d-Block elements Less reactive harder metals Includes metals used in jewelry and construction Cannot easily predict valence e-

Carbon Family Elements in group 4A Branch of chemistry based on Carbon Silicon and Germanium are important semiconductors

Halogens Group 7A Reactive Volatile Diatomic (F2,Cl2,Br2,I2) Nonmetals Always found combined with other elements in nature

Unreactive gases (Inert) Have a full valence shell The Noble Gases Group 8A Unreactive gases (Inert) Have a full valence shell

Inner Transition Metals -Have f orbitals that contain electrons -Used to be called rare-earth elements -More abundant than other metals

Representative Elements Groups 1A – 7A