Chemical Bonding And Molecular Structure

Step 1: Identify the ions involved in Calcium Carbonate.
Calcium is a Group 2 element and forms a cation with a +2 charge: Ca .
Carbonate is a polyatomic anion with a -2 charge: CO . Step 2: Determine the chemical formula by balancing charges.
To form a neutral compound, the total positive charge must balance the total negative charge.
Since calcium has a +2 charge (Ca ) and carbonate has a -2 charge (CO ), one Ca ion combines with one CO ion. The formula is therefore CaCO . Step 3: Evaluate the given options.
(1) MgCO : This is Magnesium Carbonate.
(2) Na CO : This is Sodium Carbonate.
(3) CuCO : This is Copper(II) Carbonate.
(4) CaCO : This is Calcium Carbonate. Step 4: Conclude the correct formula.
The correct formula for Calcium Carbonate is CaCO . $ _3 $