Question

write down five major differences between Mendeleev's periodic table & modern periodic table?​

Answer 1

Main differences between Mendeleev's Periodic Table and the modern periodic table: In the modern periodic table, the elements are arranged in order of increasing atomic number. (In Mendeleev's table, they were arranged in order of increasing atomic weight).

Mendaleev's periodic table contains about 66 elements. Modern periodic table contains presently 118 elements.

Mendaleev's periodic table contains about 66 elements. Modern periodic table contains presently 118 elements.In Mendeleev's periodic table there were gaps for undiscovered elements.Modern periodic table maintains uniformity.

Mendaleev's periodic table contains about 66 elements. Modern periodic table contains presently 118 elements.In Mendeleev's periodic table there were gaps for undiscovered elements.Modern periodic table maintains uniformity.In Mendeleev's periodic table noble gases were not placed (as they are not discovered at that time).In Modern periodic table noble gases in a seperate group named as group-18.

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!!!