1. Chapter 6 The Periodic Table
The how and why

2. History 1829 German J. W. Dobereiner Grouped elements into triads
Three elements with similar properties
Properties followed a pattern
Not all elements had triads

3. History Russian scientist Dmitri Mendeleev
Mid 1800 – atomic masses of elements were known
Wrote down elements in order of increasing mass
Sorted them by similar properties

4. Mendeleev’s Periodic Table
Found some gaps
Must be undiscovered elements
Predicted their properties before they were found

5. The Modern Table Ordered by increasing atomic number
Elements are still grouped by properties
Similar properties are in the same column
Added a column of elements Mendeleev didn’t know about.
The noble gases weren’t found because they didn’t react with anything.

6. Horizontal rows are called periods
There are 7 periods

7. Vertical columns are called groups.
Elements are placed in columns by similar properties.
Also called families

8. The elements in the A groups are called the representative elements

9. Other Systems IA IIA IIIB IVB VB VIB VIIB VIIIB IIIA IVA VA VIA VIIA
VIIIA IB
IIB 1 2 13 14 15 16 17 18 3 4 5 6 7 8 9 10 11 12 1A 2A 3A 4A 5A 6A 7A 8A 3B 4B 5B 6B 7B 8B 1B 2B

10. Metals

11. Metals Luster – shiny. Ductile – drawn into wires.
Malleable – hammered into sheets.
Conductors of heat and electricity.

12. Transition metals
The Group B elements

13. Non-metals
Dull
Brittle
Nonconductors- insulators

14. Metalloids or Semimetals
Properties of both
Semiconductors

15. These are called the inner transition elements and they belong here
Lanthanide
Actinide

17. Group 1A are the alkali metals
Group 2A are the alkaline earth metals

18. Group 7A is called the Halogens
Group 8A are the noble gases

19. Future Look at the Periodic Table

20. Practice!!!
Do the worksheet “Organizing Elements”