Question

List any three observations which poset a challenge to mendeleev's periodic law.

Answer 1

Answer:

Metals are not arranged in separate row

hydrogen can't have a specific place

elements aren't arranged on the basis of atomic no

Answer 2

Answer:

1.Mendeléev formulated a Periodic Law, which states that ‘the properties

of elements are the periodic function of their atomic masses’.

2.Mendeléev’s Periodic Table contains vertical columns called ‘groups’

and horizontal rows called ‘periods’.

3.Mendeléev concentrated on the compounds formed by elements with

oxygen and hydrogen. He selected hydrogen and oxygen as they are

very reactive and formed compounds with most elements.