Answer
b.
Work Step by Step
In this diagram, black spheres represent protons, white spheres represent neutrons, and the smaller white spheres surrounding the clusters represent electrons.
In $^{13}_{6}C^+$ (also called carbon-13), we have $6$ protons, which is carbon's atomic number. We figure out the number of neutrons by taking the atom's mass number $13$ and subtracting the atomic number, which is $6$ to get $7$ as the number of neutrons in this atom's nucleus. Since the atom has a positive charge, we know that there is one less electron than proton; therefore, we have five electrons.
Protons: $6$
Neutrons: $7$
Electrons: $5$
The diagram best representing this particular atom of carbon is option b.
