What is the electron configuration for bismuth (Bi)?
The Correct Answer and Explanation is:
The electron configuration for bismuth (Bi), with an atomic number of 83, is:
[Xe] 4f(^\text{14}) 5d(^\text{10}) 6s(^\text{2}) 6p(^\text{3}).
Explanation:
Electron configurations describe the distribution of electrons in an atom’s orbitals, providing insight into an element’s chemical behavior. Each orbital can hold a certain number of electrons, and these orbitals are filled in a specific order. For bismuth, this order begins with lower energy orbitals and progresses to higher ones according to the Aufbau principle, which dictates that electrons occupy orbitals from lowest to highest energy.
Bismuth has 83 electrons. Its configuration begins with the innermost orbitals and fills outward. The starting point for bismuth’s electron configuration is xenon ([Xe]), a noble gas with 54 electrons. This notation shortens the configuration, allowing us to write only the electrons beyond xenon. So, after xenon, we continue filling electrons into the 4f, 5d, 6s, and 6p orbitals as follows:
- 4f(^\text{14}): The 4f orbital holds up to 14 electrons, which are completely filled for bismuth.
- 5d(^\text{10}): The 5d orbital can hold up to 10 electrons and is also fully occupied.
- 6s(^\text{2}): The 6s orbital holds 2 electrons.
- 6p(^\text{3}): The 6p orbital can hold up to 6 electrons, but only 3 are needed for bismuth.
The final portion, 6p(^\text{3}), determines bismuth’s placement in Group 15 of the periodic table, also known as the pnictogens or nitrogen group. With three unpaired electrons in the 6p orbital, bismuth exhibits a +3 oxidation state in many compounds. This configuration contributes to bismuth’s unique properties, including its relatively low reactivity and its stability as the heaviest non-radioactive naturally occurring element. Understanding electron configurations aids chemists in predicting bonding behavior and chemical reactivity, making it a foundational concept in atomic theory and chemical periodicity.