An atom of carbon-13 (¹³C) has the following constituents:
Protons: Carbon always has 6 protons because its atomic number is 6, which defines its identity. Therefore, carbon-13 also has 6 protons.
Electrons: In a neutral atom, the number of electrons is equal to the number of protons. Hence, carbon-13, with 6 protons, also has 6 electrons.
Neutrons: The isotope notation "carbon-13" specifically refers to the mass number, which is the sum of protons and neutrons. Since carbon-13 has an atomic number of 6, it means it has 6 protons. Subtracting the atomic number from the mass number gives us the number of neutrons. Therefore, carbon-13 has 13 - 6 = 7 neutrons.
In summary, an atom of carbon-13 (¹³C) consists of 6 protons, 6 electrons, and 7 neutrons.