1. History of the Modern Periodic Table

2. During the nineteenth century, chemists began to categorize the elements according to similarities in physical and chemical properties. The result - our modern periodic table.

3. Antoine Lavoisier
In 1790’s, he had a list of 23 elements. No organization, just a list. "father of modern chemistry"

4. Johann Dobereiner Model of triads 1780 - 1849
In 1829, classified some elements into groups of three. The elements in a triad had similar chemical properties.
(ex. Cl, Br, I and Ca, Sr, Ba)
Model of triads

5. John Newlands Law of Octaves 1838 - 1898
In 1863, he suggested that elements be arranged in “octaves” because he noticed (after arranging the elements in order of increasing atomic mass) that certain properties repeated every 8th element.
Law of Octaves

6. Dmitri Mendeleev
In 1869 he published a table of the elements organized by increasing atomic mass.

7. Lothar Meyer
At the same time, published his own table of the elements organized by increasing atomic mass.

8. Mendeleev...
used his table to predict the physical properties of three elements that were yet unknown.
After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev’s predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.

9. Henry Moseley
In 1913, through his work with X-rays, he determined the actual nuclear charge (atomic number) of the elements*. He rearranged the elements in order of increasing atomic number.

10. Glenn T. Seaborg
After co-discovering 10 new elements, in 1944 he moved 14 elements out of the main body of the periodic table to their current location below the Lanthanide series. These became known as the Actinide series.

11. Glenn T. Seaborg
He is the only person to have an element named after him while still alive.
"This is the greatest honor ever bestowed upon me - even better, I think, than winning the Nobel Prize."

12. Periodic Table Geography

14. The horizontal rows of the periodic table are called PERIODS.

15. The elements in any group of the periodic table have similar physical and chemical properties!
The vertical columns of the periodic table are called GROUPS, or FAMILIES.

16. Periodic Law
When elements are arranged in order of increasing atomic number, there is a periodic pattern in their physical and chemical properties.

17. Alkali Metals

18. Alkaline Earth Metals

19. Transition Metals

20. InnerTransition Metals
These elements are also called the rare-earth elements.
InnerTransition Metals

21. Halogens

22. Noble Gases

23. The s and p block elements are called REPRESENTATIVE ELEMENTS
The s and p block elements are called REPRESENTATIVE ELEMENTS. aka GROUP A ELEMENTS

24. Classification of the Elements
Metals
Nonmetals
Metalloids

25. METALS Shiny when smooth and clean Solids at room temperature
Good conductors of heat & electricity
Most are malleable & ductile

26. NONMETALS Gases or brittle dull-looking solids
Poor conductors of heat & electricity
Include highly reactive HALOGENS (Group 7A)
Include very unreactive NOBLE GASES (Group 8A)

27. NONMETALS
Include Nitrogen & Oxygen which make up most of the air we breathe
Include CARBON which is the basic element in all organic substances

28. METALLOIDS aka “semimetals”
Physical & Chemical properties of both metals and nonmetals
Include SILICON & GERMANIUM used in computer chips and solar cells

29. Mapping Metals and Nonmetal in the Periodic Table
NONMETALS
METALS
METALLOIDS

30. The periodic table is the most important tool in the chemist’s toolbox!