In a reaction, lithium permanganate is dissolved in water.
a) What is the chemical formula of the lithium permanganate?
b) What ions are formed when the substance dissolves?
c) What is the electron configuration of the cation in the reaction?
The correct answer and explanation is :
Answers:
(a) Chemical Formula of Lithium Permanganate
The chemical formula of lithium permanganate is LiMnO₄.
(b) Ions Formed in Solution
When lithium permanganate dissolves in water, it dissociates into its constituent ions:
[
\text{LiMnO₄ (s)} \rightarrow \text{Li}^+ (aq) + \text{MnO₄}^- (aq)
]
Thus, the ions formed are:
- Lithium ion (Li⁺)
- Permanganate ion (MnO₄⁻)
(c) Electron Configuration of the Cation (Li⁺)
The lithium atom (Li) has an atomic number of 3, meaning it has three electrons in its neutral state. The electron configuration of a neutral lithium atom is:
[
1s^2 2s^1
]
When lithium loses one electron to form Li⁺, it loses the single electron in the 2s orbital, leaving:
[
1s^2
]
Explanation (300 Words)
Lithium permanganate (LiMnO₄) is an ionic compound consisting of lithium (Li⁺) and permanganate (MnO₄⁻) ions. When it dissolves in water, the strong electrostatic forces between these ions are overcome by the polar water molecules, leading to the dissociation of the compound into separate ions.
The lithium ion (Li⁺) is a simple monovalent cation. In its neutral state, lithium has three protons and three electrons, with an electron configuration of 1s² 2s¹. However, in forming Li⁺, lithium loses its outermost electron (the 2s¹ electron), leaving only two electrons in the 1s² orbital. This makes Li⁺ a stable ion because it achieves the noble gas configuration of helium (He).
On the other hand, the permanganate ion (MnO₄⁻) is a polyatomic anion, in which manganese is in the +7 oxidation state. The MnO₄⁻ ion remains intact in solution, contributing to the overall reactivity and oxidizing power of permanganates.
Since lithium is an alkali metal, it readily loses one electron to achieve a stable electron configuration. This property makes lithium highly reactive, and its compounds, including LiMnO₄, are typically soluble in water. The dissolution process is crucial in many chemical reactions, including redox processes where MnO₄⁻ acts as a strong oxidizing agent.
Overall, the dissolution of lithium permanganate illustrates fundamental ionic dissociation principles, electron configuration stability, and the role of alkali metal cations in aqueous chemistry.