Electrons are subatomic particle that contains a negative charge and it has all the characteristics that are announced:
1. Electrons are located outside the nucleus because in the nucleus we have the protons and neutrons. There's a certain difference of charge that makes that electrons speed around the nucleus.
2. Electrons move at extremely high speeds as we mentioned in the last part.
3. Electrons have specific energy levels based on the distance that they have with the nucleus.
4. Electrons have an extremely small mass because it is smaller than the protons and nucleus. You can imagine that the mass is near zero.