Question

State three points of difference between mendeleev's periodic table and modern periodic table.

Answer 1

Mendeleev periodic table was based on atomic mass

Modern periodic table is based on atomic no.

Mevdeleev periodic table was unable to place hydrogen on its correct place

Modern periodic table did

Isotopes were not there in Mendeleev periodic table

In modern periodic table there was no need to arrange isotopes as isotopes have equal no of protons

Answer 2

Answer:

• Mendeleev's periodic table

1. elements are arranged in increasing order of their atomic masses.
2. It is not divided into any blocks.
3. There are 8 groups.
4. Isotopes could not be placed properly.

• Modern periodic table

1. Elements are arranged in increasing order of their atomic numbers.
2. It is divided into four blocks, namely s-block,p-block,d-block and f-block.
3. There are 18 groups.
4. Isotopes occupy the same position as the element.

Hope you understood mate!!!