‘Hydrogen occupies a unique position in the Modern Periodic Table.' Justify the statement.

Explanation

The position of hydrogen is unique in the Modern Periodic Table. This is because:
  i] The valence-shell configuration of hydrogen and alkali metals is same - both have one electron. Thus, hydrogen has some properties similar to alkali metals and hence, it must be placed in group I.
ii] Both hydrogen and halogens require one electron to complete their valence configuration. So they show similarities in their properties and hydrogen can be placed in group 17.
iii] Hydrogen also exhibits some properties different from both alkali metals and halogens. For instance, oxides of hydrogen (such as water) are neutral whereas alkalimetals form basic oxides and halogens form acidic oxides.