Slide 1

History of the Periodic Table 1790s Antoine Lavoisier compiled a list of the 23 known elements 1864 John Newlands named the periodic relationship that he observed in chemical properties the Law of the Octaves

Slide 2

1869 Demetri Mendeleev Demonstrated a connection between atomic mass and elemental properties. Organized the first Periodic Table of the Elements Predicted the existence and properties of undiscovered elements Arranged his Periodic Table according to increasing ATOMIC MASSES of the elements

Slide 3

In 1870 there were about 70 known elements

Slide 4

In 1911 Henry Moseley Discovered that atoms of each element contain a unique number of protons in their nucleus Arranged the elements in increasing ATOMIC NUMBER rather than atomic masses as Mendeleev had done

Slide 5

Periodicity- A repeating pattern Periodic Law- States that the chemical and physical properties of elements are periodic functions of their atomic number Periodic Table- A chart organizing elements by their INCREASING atomic number.

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FAMILIES YOU MUST KNOW Family # 1- Alkali Metals Family, Lithium Francium (Li-Fr) excluding Hydrogen because it is NOT a metal. Hydrogen is a gas! Family #2- Alkaline Earth Metals, (Be Ra)

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Family # 17- The Halogens Fluorine Astatine (F At) Family # 18- The Noble Gases Helium Radon Transition Metals Families 3 12 the d block

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Periods 6 and 7 Lanthanides Rare Earth Metals, used in TV Period 6 Elements # 58 71 Very Colorful ---------------------------------------------------------------- -- Actinides Radioactive elements 90 --103 Period 7 Most are synthetic or man-made

Slide 9

Representative Elements Elements within the s and the p blocks

Slide 10

ZIG-ZAG LINE The zig-zag line separates the metals from the non metals Metals on the left of the zig-zag line Non metals to the right of the zig-zag line

Slide 11

Metalloids Metalloids are elements located next to the zig- zag line with the EXCEPTION OF ALUMINUM Metalloids include the following: Boron, B Arsenic, As Silicon, Si Antimony, Sb Germanium, Ge Telurium, Te Polonium, Po

Slide 12

Metalloids exhibit properties of both metals and non metals - They are somewhat poor conductors - called semi conductors - used in computers, cell phones, etc.

Slide 13