Question

Difference between modern periodic table and mendeelev's periodic table.

Answer 1

Differences between the Modern periodic table and Mendeleev's periodic table are:

Mendeleev's periodic table	Modern periodic table
1. Mendeleev's periodic table is based on atomic mass.	1. The modern periodic table is based on the atomic number.
2. Mendeleev's periodic table contains about 63 elements.	2. The modern periodic table contains about 118 elements
3. In Mendeleev's periodic table there were gaps for undiscovered elements.	3. The modern periodic table maintains uniformity.
4. In Mendeleev's periodic table noble gases were not placed (as they are not discovered at that time).	4. In the Modern periodic table noble gases are in a separate group named group-18.
5. In Mendeleev's periodic table transition elements are included with other elements	5. In the Modern periodic table transition elements are placed in a separate block.