Question: how many protons neutrons and electrons are there in a neutral atom of 131 i (iodine- 131 )?
Answer: Iodine has 53 protons and 53 electrons (because it has no charge the number of protons equals the number of electrons). Iodine-131 has 131 protons and neutrons. Iodine-131 has 131 minus 53 protons = 78 neutrons.