In the modern periodic table, which are the metals among the first ten elements ?

How many periodic and group are there in the long form of periodic table ?

Give two example each of (i) group 1 elements (ii) group 17 elements (iii) group 18 elements.

What is the significance of atomic number in the modern classification of elements ? Explain with the help of an example.

How were the positions of isotopes of an element decided in the modern periodic table ?