Hydrogen is in group 1a of the periodic table, known as the alkali metals, although it obviously isn't a metal. what is the reason for its placement in this group?

It's highly reactive and contains only one valence electron

In atoms, the electron carries a negative elementary or unit charge; the proton carries a positive charge. the two types of charge are equal and opposite. in an atom of matter, an electrical charge occurs whenever the number of protons in the nucleus differs from the number of electrons surrounding that nucleus.