1. Ch The Periodic Table
I. History

2. A. Mendeleev Dmitri Mendeleev (1869, Russian)
Organized elements by increasing atomic mass.
Elements with similar properties were grouped together.
There were some discrepancies.

3. A. Mendeleev Dmitri Mendeleev (1869, Russian)
Predicted properties of undiscovered elements.

4. B. Moseley Henry Mosely (1913, British)
Organized elements by increasing atomic number.
Resolved discrepancies in Mendeleev’s arrangement.

5. II. Organization of the Elements
Ch The Periodic Table
II. Organization of the Elements

6. A. Metallic Character
Metals
Nonmetals
Metalloids

7. B. Blocks Main Group Elements Transition Metals
Inner Transition Metals