Question

Distinguish between:

Mendeleev’s periodic table - Modern periodic table

Answer 1

	Mendeleev’s periodic table	Modern periodic table
1.	Elements are arranged in increasing order of their atomic masses.	Elements are arranged in increasing order of their atomic numbers.
2.	It is not divided into any blocks.	It is divided into four blocks, namely s-block, p-block, d-block and f-block.
3.	There are 8 groups.	There are 18 groups.
4.	Isotopes could not be placed properly.	Isotopes occupy the same position as the element.