1b.4 Development of the periodic table

Question 1

Who first developed the periodic table?

Answer 1

Dmitri Mendeleev (1869), Russian chemist

Question 2

How did they develop the period table?

Answer 2

Sorted elements based on their properties (and the properties of their compounds), and their atomic mass, to make columns

Where there were inconsistencies he left gaps but ensured elements with the same properties were in the same columns

Question 3

Give an example of how they predicted the properties of an undiscovered element.

Answer 3

He could predict the properties of the elements that were undiscovered but in the “gaps” in his table, as they should follow the patterns of properties of the elements already in the table.

For example, he correctly predicted the properties of germanium (which he called “ekasilicon”)