In organic molecules, an exciton is a particle bound pair of an electron (negative charge) and its hole (positive charge). They are held together by Coulombic attraction and can move within ...

Normally, the positive and negative charges cancel out because there are the same number of each. So the atom has no overall charge - it is neutral. But when you rub one, neutral, electrically ...

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 ...