Question

__________ has both the characteristics of Alkali metals and halogens.

(a) Helium

(b) Chlorine

(c) Sodium

(d) Hydrogen

I had been asked this question in class test.

The above asked question is from Electronic Configurations and Types of Elements: s, p, d and f Blocks in portion Classification of Elements and Periodicity in Properties of Chemistry – Class 11

Answer 1

Right choice is (d) Hydrogen

To elaborate: As per the outer shell configuration of hydrogen (that is 1s^1), it has only one electron in s-orbital making it eligible as an Alkali metal. It requires only 1 electron to obtain a noble gas configuration, which is a characteristic of halogen.