Question

how to show that the position of hydrogen is just above group 17

Answer 1

Basically every element in 17th group tries to gain an electron , due to electro-negativity value ! Whereas every 1st A group element tries to loose 1 electron , We can't decide where to place hydrogen, because it has 2 possibilities, 1st group and 17th group, as hydrogen makes covalent bond to attain duplet rule, and as it have properties of 17th group , It can also be placed in 17th group, but when it comes to atomic number it is appropriate to place it in 1st group !!

hope you understand ! If I am wrong at any point I am sorry !