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 ...

An element's atomic number defines it. An element with 17 protons will always be chlorine. However an element's mass numbers can vary, which means that it can have different numbers of neutrons.

Graphene is perfectly selective to protons and blocks even smallest ions like chlorine, University of Manchester research shows. This result will be important for the development of graphene-based ...