The electron is a negatively charged subatomic particle, and it is one of three main subatomic particles (the others being the proton and the neutron) that make up atoms. Electrons are responsible for bonding atoms together to make molecules, and they are also the carriers of electric charges in the conducting materials found in the electronic devices you use every day. While protons and neutrons are both found in the center, or nucleus, of an atom, electrons are located apart from the nucleus and are best described as a cloud of electron density. Most reactions in chemistry deal with changes to the arrangement of electrons in some form.