Final answer:
The isotope with 36 electrons in a neutral atom is Kr-80, which has 36 protons, 36 electrons, and 44 neutrons.
Step-by-step explanation:
The isotope with 36 electrons in an atom is Kr-80 (option b: 80 36 Kr). This is because the number of electrons in a neutral atom is equal to the atomic number (Z), which is the number of protons. Krypton has an atomic number of 36, so a neutral Kr atom would also have 36 electrons. The notation 80 36 Kr indicates a mass number (A) of 80, meaning this isotope of krypton has 80 - 36 = 44 neutrons.