Q. Among the alkali metals caesium is the most reactive because
A) Its incomplete shell is nearest to the nucleus.
B) It has a single electrons in the valence shell.
C) It is the heaviest alkali metal.
D) The outermost electron is more loosely bound than the outermost electron of the other alkali metals.
Explanation
(d)
Alkali metals have a tendency to lose the single valence electron and form positive ion and gain inert gas configuration but in case of caesium, the distance of the valence electron is maximum. So, force of attraction by the nucleus is least, hence, it is more reactive.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.