Answer:
The correct answer is barium.
Step-by-step explanation:
Valence electrons are the electrons present in the valence shell of an atom of an element.
Bismuth has atomic number of 83.
![[Bi]=[Xe]6s^26p^3](https://img.qammunity.org/2018/formulas/chemistry/high-school/wn0fy8dvpcfowqdqkmwbko86lv10gcmqad.png)
Number of valence electron = 5
Boron has atomic number of 5.
![[B]=[He]2s^22p^1](https://img.qammunity.org/2018/formulas/chemistry/high-school/wli65qxl17je1ydl724lrmj3gpws7z0bl8.png)
Number of valence electron = 3
Barium has atomic number of 56.
![[Ba]=[Xe]6s^2](https://img.qammunity.org/2018/formulas/chemistry/high-school/xkrxzxjxy27ytb0aigom72g0xnm5z2cmcj.png)
Number of valence electron = 2
Bromine has atomic number of 35.
![[Br]=[Ar]4s^24p^5](https://img.qammunity.org/2018/formulas/chemistry/high-school/29kli8m4fnz2wkpd9jugu2m9ucy11zwuc6.png)
Number of valence electron = 7
Barium is one of the element in the given options which possesses fewest number of valence electrons