Electrons are the particles that have a negative charge. Protons are the particles that have a positive charge. There are also neutrons which have a neutral charge. A lot of these particles are found in atoms and molecules. They do different things. The electron was discovered back in 1897 by J. J. Thomson. It has a mass of 9.109 times ten to the negative thirty-first power of kilograms.
It has a half spin. It was theorized though earlier than 1897 because Richard Laming and G. Johnstone Stoney and a few others speculated it in 1838-1851 and 1974 respectively. When two electrons come together chemically, they are bonded together. This type of bond where electrons are shared is called a covalent bond.