For example, the atomic number of chlorine is 17. Every chlorine atom has 17 protons and 17 electrons ... but they can be the same. For example, the mass number of argon atoms and calcium atoms ...

The relative charge of a nucleus is the same as its proton (atomic) number. Key fact ... (hydrogen-3): if the atom loses one or more electrons, it becomes a positively-charged ion if the atom ...

Elements that have the same number of electrons in their outermost shells ... to train a new generation of physicists. But his atomic model remains the best known work of a very long career.

Try to keep the same number of neutrons and protons as you build your atom. If the imbalance is too great, radioactive decay will occur. Up to two electrons may exist in the atom's first shell.