Suggest reasons for and against the inclusion of hydrogen in the main group of the periodic table

See explanation

Explanation:

Hydrogen has only one valence electron. Sometimes, hydrogen is included as part of group 1 or 17 in the periodic table. Is this correct? Well, the answer to this question is not so straight forward!

Let us remember that hydrogen forms a univalent positive ion H^+ just like the group 1 elements, but it also forms a univalent negative ion H^- just like group 17 elements. Also, hydrogen is a gas and forms a molecular diatomic compound just like group 17 elements. This is not the case with other group 1 elements. We can see that hydrogen is chemically and physically dissimilar to other group 1 elements hence one can logically argue against its inclusion in group 1. Also, it is not a halogen, so we can also argue against its inclusion in group 17.

However, it is convenient to include hydrogen in the main groups 1 or 17 when discussing its chemical properties in order to make it easier to assimilate. If we place hydrogen in group 1, we can understand that it forms univalent positive ions. Similarly, if we place it in group 17, we understand that it forms univalent negative ions.

Most times hydrogen is just written separately at the top right corner of the periodic table and not as a member of any group because of the issues outlined above.

fe 55.85 g/mol and h2o 18.02 g/mol.