Why is it such that calcium carbonate formula is CaCO3 while sodium/potassium carbonate is Na2CO3,K2CO3 respectively?And what is the charge of CO3?Thanks

Expert Answers
jerichorayel eNotes educator| Certified Educator

To better illustrate this problem, the knowledge of the charges of the ions is necessary. 

Na2CO3 is formed when Sodium and Carbonate ions are combined. Sodium ion has a charge of +1 and Carbonate ions has a charge of -2.  Remember the "crisscross" method when dealing with this problem.

`Na^(+1) + CO_3^-2 -> Na_2CO_3`

Same as with K.

`K^(+1) + CO_3^-2 -> K_2CO_3`

In the case for Calcium, it has a charge of +2. When you do the crisscross method, the subscript will have both 2 and it will be cancelled.

`Ca^(+2) + CO_3^-2 -> CaCO_3`







pramodpandey | Student

In CaCO3  , 



`` only one Ca required




valency here for Na and K are (+1) and CO3  is (-2)

so we need 2 Na and 2 Potassium molecules.