1. The Periodic Table of Elements

2. Early Versions 1830: 55 elements had been discovered
1860’s: Dimitri Mendeleev discovered a system that applied to all elements

3. Mendeleev Father of the periodic table Noticed patterns when the
elements were
arranged by
increasing
atomic mass

4. Mendeleev Noted properties of elements
Melting point
Density
Color
Studied atomic mass and chemical bonds
Compared mass to hydrogen

5. Mendeleev
Noted that arranging elements according to atomic mass did not always produce similar groups
Moved element cards into groups where they fit best
Predicted other elements and their properties

6. Mendeleev
1869: Published the 1st periodic table

7. The Modern Periodic Table
New elements were added as they were discovered
Early 1900’s: scientists learned about the atomic number

8. Reading the Periodic Table
Contains
over 100 squares:
one for each element

9. Reading the Periodic Table
An element’s properties can be predicted from its location on the periodic table.
groups/families
periods

10. Groups/Families Elements in columns 18 columns
Elements in each group have similar characteristics.
Example: Group 1 are metals that all react violently with water; Group 17 reacts violently with elements from Group 1; Group 18 rarely reacts at all

11. Groups/Families
EXAMPLES OF FAMILIES - Alkali Metals - Alkaline Earth Metals - Transition Metals - Halogen Gases - Inert Gases (Noble Gases)

12. Periods Horizontal rows
Series of different elements from different groups
Have very different properties

13. Why it Works!
It’s based on the structure of atoms, especially the valence electrons!