An atom of which element is the least reactive?
A)hydrogen (atomic number 1)
B)lithium (atomic number 3)
C)chlorine (atomic number 17)
D)argon (atomic number 18)
E)scandium (atomic number 21)

Question

Quizplus · Accepted Answer

The reactivity of an element depends on its electron configuration and the tendency to gain or lose electrons to achieve a stable configuration. Argon has a complete valence shell, so it is already in a stable configuration and does not need to gain or lose electrons. Therefore, it is the least reactive element among the given options.

An Atom of Which Element Is the Least Reactive