The nucleus is very small compared to the atom as a whole: as electrons are even smaller, most of an atom is empty space the diameter of a nucleus can be 100,000 times less than the diameter of an ...

They have a radius of around 1 × 10 10 metres. This symbol shows that chlorine has 35 particles in the nucleus (protons and neutrons), 17 of which are protons. It also tells us that chlorine has ...

The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus. The electron and proton are attracted to each other.