Question

Can anyone say the easy method to memories periods table or at least first 20 elements

Answer 1

I think u should learn first 20 element by name .

Answer 2

The best trick is to make a mnemonic. I had also made a one and remembered the whole periodic table. Any can be made, u can spend your 30 mins for this then u will also be able to make a one. I can give u a example:
Na Maango Alla Sie Paisa
This is Sodium, Magnesium then Aluminium, Silicon and Phosphorus.
And can be easily remembered like a game.
Regards