1. Mendeleev & The Periodic Table

2. Mendeleev for a Day Activity

3. Mendeleev’s Table
Organized elements by increasing atomic mass so that elements with similar properties were in the same column.

4. Mendeleev’s Prediction
After Mendeleev placed all the known elements in his periodic table, several empty spaces were left.
In 1871 Mendeleev predicted the existence and properties of elements that would fill three of the spaces.
By 1886, all three of these elements had been discovered.

6. Mendeleev’s Prediction
Predicted Eka-aluminum in 1871
Soft metal
Low melting point
Density of 5.9 g/cm3
Found: Gallium in 1875
Melting Point 29.7 C
Density of 5.91 g/cm3

7. Mendeleev’s Predictions

8. Usefulness of His Table
The close match between Mendeleev’s prediction and the actual properties of new elements showed how useful his periodic table could be.

9. Henry Moseley (1913, British)
Organized elements by increasing atomic number.
Fixed problems in Mendeleev’s arrangement.