Question

Difference in mendeleev's periodic law and lodern periodic law

Answer 1

Here goes your difference..

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•Mendeleev's periodic table is based on atomic mass

•Modern periodic table is based on atomic number

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•Mendaleev's periodic table contains about 66 elements.

•Modern periodic table contains about 112 elements

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•In Mendeleev's periodic table there were gaps for undiscovered elements.

•Modern periodic table maintains uniformity.

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•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.

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•In Mendeleev's periodic table transition elements included with other elements .

•In Modern periodic table transition elements placed in separate block.

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Hope it helps !!!

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!!!