It also tells us that chlorine has 18 neutrons (35 - 17) and, as the number of electrons and protons are equal in a neutral atom, chlorine also has 17 electrons. The relative mass of a nucleus is ...

To get to grips with it, it helps to first understand that atoms, the basic units of all matter, are made of protons, neutrons ... of electrons in an atom. Let’s take chlorine as an example.

The attraction by the chlorine atoms is stronger than the attraction by the calcium atom. Two electrons are transferred from the calcium atom, one to each chlorine atom. Calcium becomes a +2 ion and ...

The atom is a complex system of particles. It's made up of a central nucleus consisting of protons and neutrons, called ...