There are following similarities of hydrogen with halogens :
(i) Electronic Configuration :
Electronic configuration of hydrogen = \(1 s^{1}\)
General electronic configuration of halogens = ns2np5
i. e., Hydrogen requires one electron to attain noble gas configuration. Similarly, halogens also require one electron to attain noble gas configuration.
(ii) Electronegative Nature : Hydrogen has tendency to attract electrons like halogens.
e.g., H + e– ➝ H– (hydride ion)
Cl + e– ➝ Cl– (chloride ion)
(iii) Oxidation number: In addition to oxidation state of +1, hydrogen shows oxidation state of -1 like halogens in some of its compounds
e.g., NaH (Oxidation state of H = -1)
NaCl (Oxidation state of Cl = -1)
(iv) Valency : Valency of hydrogen is 1 like halogens.
(v) Reaction with metals : hydrogen combines with metals to form binary compounds similar to halogens.
e.g., 2Na + H2 ➝ 2NaH
2Na + Cl2 ➝ 2NaCl
(vi) Atomicity: Hydrogen exists in diatomic form (H2) like halogens (e.g., Cl2).