Carbon-12, carbon-13, and carbon-14 are discussed. Carbon-12 has 6 protons, 6 neutrons, and 6 electrons and is referred to as normal carbon. Carbon-13 has 6 protons and electrons but 7 neutrons, while carbon-14 has 6 protons and electrons but 8 neutrons. However, carbon-13 and carbon-14 have the same properties as carbon-12.