Give the chemical formula for the carbonate ion. Remember to include the charge.
The Correct Answer and Explanation is :
The chemical formula for the carbonate ion is CO32−\text{CO}_3^{2-}. It consists of one carbon atom (C) and three oxygen atoms (O), and the overall charge of the ion is -2.
Explanation:
- Carbonate Ion Structure:
- The carbonate ion is a polyatomic ion, meaning it is made up of more than one atom. In this case, it consists of a central carbon atom covalently bonded to three oxygen atoms.
- The carbon atom in the carbonate ion forms double bonds with two of the oxygen atoms, and the third oxygen is involved in a single bond. However, due to resonance, the actual bonding is a blend, meaning the bonds between carbon and oxygen are not purely single or double, but rather intermediate. This means that all three C–O bonds are of equal length, which is a key characteristic of the carbonate ion.
- Resonance:
- The carbonate ion exhibits resonance, which means that the electron distribution is delocalized. This means that the negative charge is spread evenly over the three oxygen atoms, leading to an overall -2 charge on the ion. This delocalization of electrons contributes to the stability of the ion.
- Charge Distribution:
- In the carbonate ion, the negative charge is not localized on a single oxygen atom but is distributed over the three oxygen atoms. Each oxygen atom in the ion has a partial negative charge, which helps balance the overall charge of -2.
- Significance in Chemistry:
- The carbonate ion is a key component in various chemical reactions, particularly in the formation of carbonates, such as calcium carbonate (CaCO3\text{CaCO}_3), and in the buffering systems in biology that regulate pH levels.
In summary, the carbonate ion is a stable polyatomic ion with the formula CO32−\text{CO}_3^{2-}, and its resonance structure plays a crucial role in maintaining the stability and behavior of this ion in various chemical contexts.