Hydrogen combines with halogens, oxygen and sulphur to form compounds having similar formulae as alkali metals.
A. Both (I) and (II)
B. Both (II) and (III)
C. Both (I) and (IV)
D. Both (III) and (IV)
Answer:C
Hydrogen combines with halogens, oxygen and sulphur to form compounds having similar formulae as alkali metals.
A. Both (I) and (II) B. Both (II) and (III) C. Both (I) and (IV) D. Both (III) and (IV)
Explanation: As Mendeleev’s periodic table was based on atomic mass, no fixed position could be assigned to hydrogen. However, it has one valence electron just like alkali metals Li, Na, K etc. Moreover, hydrogen combines with haLogens, oxygen and sulphur just like alkali metals do. However, hydrogen combines with metals and non-metals to form covalent bonds by sharing of electrons and exists as diatomic molecules like halogens.