Question

Though hydrogen is a gas, it is placed in reactivity series. Why?

Answer 1

Answer:

In the periodic table, hydrogen is placed in the first row just before inert gas Helium. Because it has one electron in its valence shell, it shows reactivity that resembles electropositive metals (lose an electron and become H+) and reactivity that resembles electronegative non-metals (gain an electron and become H-).

Answer 2

Answer:

Hydrogen is included in the reactivity series of metals because it's property of electroposivity (i.e losing electron to form positive ion) is similar to that of metals, that is why we can relate it with metals.