Why wasn hydrogen included in Group 17?
Hydrogen doesn’t have a natural place in any column. That’s one of the defects with the “classic” periodic table. It has 1 electron in its outer (only) shell, so it is placed above group one. But iti is not a metal. Similar to group 17, it will attract one electron to complete its shell. But it is not a halogen either. A good periodic table shows hydrogen by itself.
