In balancing nuclear decay types of reaction, the same as balancing a chemical reaction, we use the number and the type of nucleons present for the decay reaction. Regardless of the type of decay, it should be that the total number of nucleons in the shole process should be conserved. For carbon-11, the decay equation would be as follows:
11/6 C --->11/5 B + 0/1β
It is an example of a positron emmision or a positive beta decay. It is a decay for neutron-poor nuclei where a proton is being transformed into a neutron and also emitting a positron that is high in energy.