Q. According to Mendeleev's periodic classification, the electronic configuration of hydrogen atom resembles that of alkali metals, which are given below as :

On the other hand like halogens, hydrogen also exist as diatomic molecules, such as : , etc.
On the basis of above information hydrogen can be placed with :

 2043  191 Classification of Elements and Periodicity in Properties Report Error

Solution:

Correct answer is (c) Both (a) and (b)