The Periodic Table

An Introduction

Johann Dobereiner

• 1829• Organized the elements into triads, or

groups of three based on properties.

John Newlands

• 1863• Organized the elements by octaves, or

groups of eight, because some properties repeated every 8th element.

Dmitri Mendeleev• 1869• Published a table of the elements arranged by

increasing atomic mass.• Called the “Father of the Periodic Table”• Left gaps on his periodic table for elements that

had not yet been discovered.

Henry Moseley• 1913• Rearranged the periodic table in order of

increasing atomic number.• Called the “Father of the Modern

Periodic Table”

And Now We Have This Beauty!

I Bet There are Interesting Things About the Periodic Table I have to

Memorize!

• Columns (up and down) = Groups or Families

• Rows (across)= Periods

That was easy….what’s next?

Metals, Nonmetals, and Metalloids

B

Si

Ge As

Sb Te

At

Properties of…

Metals Nonmetals Metalloids•Solid (except Hg)•Shiny•Conduct heat & electricity•Ductile: can be stretched into wire•Malleable: can be hammered into sheets•Lose e- easily

•Opposite of metals.*Includes Hydrogen

•Brittle (break easily)•Poor conductors of heat & electricity•Tend to gain electrons in chemical reactions

•Properties a mix of metals and nonmetals.•Partially conduct electricity.

How About Some of the Other Families?

• Alkali Metals: far left column• All soft metals that react violently with

water to make Hydrogen gas.

• Alkaline Earth Metals: group 2• All are shiny, silvery-white, and somewhat

reactive.

• Transition Metals: d block• Very hard with high melting and boiling

points (except Hg, of course)

• Halogens: group 7• 7 valence electrons• Highly reactive, especially with alkali

metals and alkaline earth metals

• Noble Gases: far right column• Full outer shells = nonreactive• All gases at room temperature