Hydrogen resembles alkali metals in the following aspects.
1. Electronic configuration 1s1 as alkali metals have ns1 .
2. Hydrogen forms unipositive H+ ion like alkali metals Na+, K+ .
3. Hydrogen form halides (HX), oxides (H2O) peroxide (H2O2 ) like alkali metals (NaX. Na2O, Na2O2 ).
4. Hydrogen also acts as reducing agent like alkali metals. Hydrogen resembles halogens in the following aspects.
5. Hydrogen has a tendency to gain one electron to form hydride ion (H- ) as halogens to form halide ion. (X- ).
6. Comparing the properties of hydrogen with alkali metals and with halogens, we can conclude that hydrogen resembles more alkali metals. In most of the compounds hydrogen exist in +1 oxidation state.
7. Therefore, it is reasonable to place the hydrogen in group 1 along with alkali metals as shown in the latest periodic table published by IUPAC.