Question

1)Why do we classify elements?
2)Two criteria used by Mendeleev in creating periodic table?
3), why did mendeleev leave some gap in his periodic table?

Answer 1

1. Because so that we can remember all the elements.

2.two criteria used:-

(a) increasing atomic mass.

(b) leaving gaps between the elements.

3. Because he know that in future more elements will be found.So,that he leave space.

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