The telluric helix was given by

Fill in the blanks given below:
$(i)$ The first scientist to think about the properties of elements was ......... .
$(ii)$ The relationship of properties of elements suggested by Dobereiner is known as ........... .
$(iii)$ The Law of Octaves was proposed by the chemist ......... .
$(iv)$ The first periodic table was constructed by .......... and .......... .

Mendeleev's periodic law is based on

Which elements did Mendeleev leave gaps for in his periodic table and what names did he give them?

"The properties of the elements are periodic function of their atomic numbers." This statement was given by:

The modern periodic table is based on the atomic number of the elements. The experiment which proved the significance of the atomic number was: