The Periodic TableThe Periodic Table

Groups of the Table and A Groups of the Table and A Brief HistoryBrief History

The Father of the Periodic TableThe Father of the Periodic Table—Dmitri Mendeleev—Dmitri Mendeleev

Mendeleev (1834-1907) was the first Mendeleev (1834-1907) was the first scientist to notice a relationship scientist to notice a relationship between the elementsbetween the elements

Around 1865 he arranged his periodic Around 1865 he arranged his periodic table by atomic masstable by atomic mass

Said properties of unknown elements Said properties of unknown elements could be predicted by the properties of could be predicted by the properties of elements around the missing elementelements around the missing element

Dmitri Mendeleev

The Periodic TableThe Periodic TableHenry Moseley Henry Moseley

(1887-1915) later (1887-1915) later discovered that the discovered that the periodic nature of periodic nature of the elements was the elements was associated with associated with atomic number, not atomic number, not atomic mass.atomic mass.

The Periodic TableThe Periodic Table

Column = Group or Family

18 columns on the Periodic

Table

Row = Period7 rows on the Periodic Table

What does the information in What does the information in the box tell me?the box tell me?

11

HH1.0081.008

Atomic Number = # of protons and # of electrons

Atomic Mass = # of

protons plus

neutrons

Elemental

Symbol

Metals, Nonmetals, and Metals, Nonmetals, and MetalloidsMetalloids

Metals are to the left of the

stair- step

Hydrogen (H) the only

nonmetal on the metal

side

Nonmetals are on the right of the

stair-step

Semi-metals, “metalloids,”touch the stair-step

VALANCE ELECTRONSThe electrons that are in the outermost

energy level of any atom. Examples:

Hydrogen has 1 valance electron

Oxygen has 6 valance electrons Argon has 8 valance

electrons

Boron has 3 valance electrons

8 VALANCE ELECTRONS In order to feel and be

stable, all atoms would like to have 8 valance electrons. If they don’t already have 8 they will react very well and bond with others that can add up to 8. Example: Oxygen has 6 valance electrons and reacts very easily with 2 Hydrogen atoms to form H2O, water.

The Groups of the Periodic The Groups of the Periodic TableTable

Group 1 or 1a: Group 1 or 1a: The Alkali MetalsThe Alkali MetalsMost reactive metals on the PTMost reactive metals on the PTRarely found free in natureRarely found free in natureCharge of +1, Charge of +1, 1 valence electron1 valence electron

Group 2 or 2a: Group 2 or 2a: The Alkaline Earth The Alkaline Earth MetalsMetalsStill quite reactiveStill quite reactiveCharge of +2, Charge of +2, 2 valence electrons2 valence electrons

T he Groups of the Periodic T he Groups of the Periodic TableTable

Groups 3-12 or 3-12b: Transition Groups 3-12 or 3-12b: Transition MetalsMetalsFound freely and in compounds in Found freely and in compounds in

naturenatureCharge is usually +2 but can vary—Charge is usually +2 but can vary—

usually 2 valence electronsusually 2 valence electrons

Group 13 or 3a: Group 13 or 3a: Boron FamilyBoron FamilyCharge is +3, Charge is +3, 3 valence electrons3 valence electrons

The Groups of the Periodic The Groups of the Periodic TableTable

Group 14 or 4a: Group 14 or 4a: The Carbon The Carbon FamilyFamilyContains elements that can form Contains elements that can form

unusual bonds (carbon and silicon)unusual bonds (carbon and silicon)Charge is +4 or -4, contains 4 valence Charge is +4 or -4, contains 4 valence

electronselectrons

Group 15 or 5a: Group 15 or 5a: The Nitrogen The Nitrogen FamilyFamilyCharge is -3, contains 5 valence Charge is -3, contains 5 valence

electronselectrons

The Groups of the Periodic The Groups of the Periodic TableTable

Group 16 or 6a: Group 16 or 6a: The Oxygen FamilyThe Oxygen Family Also known as the chalcogensAlso known as the chalcogensCharge is -2, 6 valence electronsCharge is -2, 6 valence electrons

Group 17 or 7a: Group 17 or 7a: The HalogensThe HalogensMost reactive nonmetalsMost reactive nonmetals charge is -1, charge is -1, 7 valence electrons7 valence electrons

Group 18 or 8a: Group 18 or 8a: The Noble GasesThe Noble Gases (The (The InertInert Gases) Gases)Inert means Nonreactive,Inert means Nonreactive, don’t don’t

normally react with other elementsnormally react with other elementsCharge is 0, Charge is 0, 2 or 8 valence electrons2 or 8 valence electrons

Special Rows on the PTSpecial Rows on the PT

Lanthanides

ActinidesWe call these rare earth metals because they are rarely found on earth.