Question

How many protons, neutrons and electrons are in an atom with an atomic 5 points

number of 20 and an atomic mass of 40?*
20 protons, 20 electrons, 20 neutrons
20 protons, 20 electrons, 40 neutrons
20 protons, 10 electrons, 20 neutrons

Answer 1

By definition, atoms have no overall electrical charge. That means that there must be a balance between the positively charged protons and the negatively charged electrons. Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons.