Question

Which element has the lowest first ionization energy?

• A. $As$
• B. $P$
• C. $N$
• D. $Bi$
• E. $Sb$

Answer 1

The correct option is D $Bi$

All the given options of elements belong to the same group $5^{th}$. The value of ionization energy (IE) decreases down the group due to the increasing size as the valence electrons are more loosely bound. Thus lowest IE in this case is of $Bi$ as it is bottom most element.