What is the charge on the barium ion? (The symbol for barium is Ba)
The Correct Answer and Explanation is:
The charge on the barium ion (Ba) is +2.
Explanation:
Barium is an alkaline earth metal, located in Group 2 of the periodic table. Elements in Group 2 typically form ions by losing two electrons to achieve a stable electron configuration, similar to the nearest noble gas. To understand why barium forms a +2 ion, let’s explore its atomic structure.
Atomic Structure of Barium:
- Atomic number of barium (Ba): 56. This means barium has 56 protons and 56 electrons in its neutral state.
- Electron configuration: The electron configuration of barium is:
[
[Xe] 6s^2
]
where [Xe] represents the electron configuration of xenon (the noble gas preceding barium in the periodic table), and the “6s²” indicates that barium has two electrons in its outermost (6th) shell.
Tendency to Lose Electrons:
Barium, as an element in Group 2, has two electrons in its outermost shell (the 6s orbital). In order to achieve a more stable electron configuration, similar to the nearest noble gas (xenon), barium tends to lose these two valence electrons. By losing these electrons, barium’s electron configuration becomes:
[
[Xe] \quad \text{(core configuration, no electrons in the outer shell)}
]
After losing two electrons, barium has a net positive charge because it now has more protons (56) than electrons (54). The result is a barium ion with a charge of +2.
Why the +2 Charge?
- The removal of two negatively charged electrons leaves the barium ion with a positive charge.
- The resulting barium ion is symbolized as ( \text{Ba}^{2+} ), indicating that it has a 2+ charge.
This behavior is typical for alkaline earth metals, such as magnesium (Mg), calcium (Ca), and strontium (Sr), all of which form ions with a +2 charge. The +2 charge helps these elements attain a more stable electronic structure.