Hydrogen resembles alkali metals, i.e., Li, Na, K, Rb, Cs and Fr of group I of the periodic table in the following respects
(i) Like alkali metals, hydrogen also contain one electron in its outermost (valence) shell and exhibit +1 oxidation state.
(ii) Like alkali metals, hydrogen also loses its only electron to form hydrogen ion, i.e., H+ (proton).
(iii) Like alkali metals, hydrogen combines with electronegative elements (non-metals) such as oxygen, halogens and sulphur forming their oxides, halides and sulphides respectively.
(iv) Like alkali metals, hydrogen also acts as a strong reducing agent,
