Compare hydrogen and halogens on the basis of :

(i) Physical state

(ii) ion formation

(iii) valency

(iv) reaction with oxygen

(i) Like halogens (fluorine and chlorine), hydrogen too is a gas.

(ii) Both show a tendency to form anions since they are one electron short of the nearest inert gas configuration.

H + e^- ⟶ H^-

Cl + e^- ⟶ Cl^-

(iii) Both have the valency 1.

(iv) Hydrogen reacts with oxygen to form neutral oxides (H₂O); Halogen reacts with oxygen to form acidic oxides (Cl₂O, Cl₂O₇ etc.)