* Protons: 34
* The atomic number of selenium is 34, which means every selenium atom has 34 protons.
* Neutrons: 46
* The mass number (80) represents the total number of protons and neutrons.
* To find the number of neutrons, subtract the atomic number from the mass number: 80 - 34 = 46
* Electrons: 34
* Atoms are electrically neutral, so the number of electrons always equals the number of protons.
In summary: An atom of selenium-80 contains 34 protons, 46 neutrons, and 34 electrons.
