Here's why:

* Electron Configuration: The electron configuration of bismuth is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³.

* Valence Electrons: Valence electrons are the electrons in the outermost energy level. For bismuth, these are the electrons in the 6s and 6p orbitals.

* Total Valence Electrons: There are 2 electrons in the 6s orbital and 3 electrons in the 6p orbital, giving a total of 2 + 3 = 5 valence electrons.