Chemistry
Answer
Hydrogen is the first element of the periodic table. Its atomic number is 1, and it has only one electron in its valence shell. Therefore, it belongs to the first group and the first period of the periodic table.
As hydrogen shows a dual nature, it resembles alkali metals of Group IA and the halogens of Group VII A (17). Thomson suggested a separate position for hydrogen. He puts hydrogen at the top of the periodic table, that does not disturb the symmetry of the periodic table.
Related Questions
Why does hydrogen show dual nature?
Compare hydrogen with alkali metals on the basis of :
(i) Ion formation
(ii) Reducing power
(iii) Reaction with oxygen
(iv) Oxide formation
In what respect does hydrogen differ from
(i) Alkali metals
(ii) Halogens
Give the general group study of hydrogen with reference to:
(i) valence electrons
(ii) burning
(iii) reducing power.