There are following similarities of hydrogen with alkali metals:
1. Electronic Configuration : The electronic configuration of hydrogen is \(1 s^{1}\) which is similar to the outermost electronic configuration of alkali metals (\(n s^{1}\)). So, it is placed with alkali metals in group 1.
2. Electropositive Character : Hydrogen can form unipositive ion by losing one electron like alkali metals.
e.g., H ➝ H+ + e–
Na ➝ Na+ + e–
3. Oxidation State : Hydrogen exhibits oxidation state of +1 ion the compounds of hydrogen which is similar to alkali metals.
4. Valency : Valency of hydrogen is 1 like alkali metals.
5. Reaction with Non-metals : Like alkali metals, hydrogen forms binary compounds with non-metals.
6. Reducing nature : Hydrogen is a good reducing agent like alkali metals.