Question

What charge on a carbonate ion $\left( C{{O}_{3}}^{2-} \right)$ ? Compared to the number of protons how many electrons does the carbonate ion have?

Answer 1

Hint: In the carbonate ion, carbon atom is bonded with single bonds to two oxygen atoms and with a double bond to an oxygen atom. It is a polyatomic ion with chemical formula $\left( C{{O}_{3}}^{2-} \right)$. It is also a conjugate base of a hydrogen carbonate.

Complete step by step solution:
Let us study about the given ion i.e. carbonate ion in detail to answer the given question easily;
Carbonate-
Carbonate is an oxoanion of carbon. As we know that it is represented as $\left( C{{O}_{3}}^{2-} \right)$ thus, we can say that the formal charge on it is ‘-2’.
Protons-
These are the positively charged particles in the volume of an atom. In short, they are the subatomic particles with mass of 1, approximately and a charge of +1. Thus, for each proton we can say that the charge is increased by one.
Electrons-
These are the negatively charged particles in the volume of an atom. In short, they are the subatomic particles with mass of o, approximately and a charge of -1. Thus, for each electron we can say that the charge is decreased by one.

Therefore, in the carbonate ion as the charge is -2; it has 2 more electrons than protons.

Note: In the carbonate ion, doubly bonded oxygen is neutral whereas, each of the single bonded oxygen has a negative charge. Thus, this is responsible for overall charge as ‘-2’.
Here, we have heard of formal charge; it is the charge assigned to an atom in the molecule.