where should hydrogen be placed in modern periodoc table?

Hydrogen is placed separately in the modern periodic table.

It can be placed in Group 1 because it has one electron in the outermost shell. Group I elements alos havve one electron in the valence shell. The outer elemctron configuration is ns¹ . However,, unlike alkali metals, it has a very high ionization enthalpy and does not possess metallic characteristics under normal conditions.

It can be placed in Group 17 also because hydrogen needs one electron to complete its valence shell. Group 17 elements also need one electron to complete their valence shell.However, in terms of reactivity, it is very low as
compared to halogens.

Inspite of the fact that hydrogen, to a certain extent resembles both with alkali metals and halogens, it differs from them as well.Thus, it is unique in behaviour and is, therefore, best placed separately in theperiodic table.