Quarks are the reason protons have a positive charge. Each quark has a fraction of an electric charge. A proton has two up ...

Molecular crystals with conductivity and magnetism, due to their low impurity concentrations, provide valuable insights into valence electrons. They have helped link charge ordering to ...

Elements in the same horizontal row are in the same period. The periods are numbered from top to bottom. The period number is the same as the number of occupied electron shells.

The “lead” of a pencil is actually made of a substance called graphite which is made of carbon atoms. The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and ...