Question

Halogens have similar reactivity because :

• A. they have the same number of protons
• B. they have the same number of electrons
• C. they have similar outer shell electron configurations
• D. they have valence electrons with the same quantum numbers
• E. they have the same number of neutrons

Answer 1

The correct option is C they have similar outer shell electron configurations

Halogens have similar reactivity because they have similar outer shell electron configurations of $n{s}^{2}n{p}^5$.
Thus, all halogens gain one electron to complete octet. Thus, they form uni-negative ion (anion).