* Special Relativity: Einstein's theory of special relativity dictates that nothing with mass can travel at the speed of light. As an object approaches the speed of light, its mass increases infinitely, requiring an infinite amount of energy to accelerate it further.

* Electron Mass: Electrons have a non-zero rest mass. While they can be accelerated to very high speeds (close to the speed of light) in particle accelerators, they never actually reach it.

However, electrons can exhibit some behaviors that might seem like they're moving at the speed of light:

* Wave-Particle Duality: Electrons behave like both particles and waves. The wave nature of an electron can propagate at speeds close to the speed of light, even though the electron itself doesn't.

* Electromagnetic Radiation: When electrons change energy levels, they emit photons (light particles). These photons travel at the speed of light, but they are not the electron itself.

In summary:

* An electron cannot travel at the speed of light because it has mass.

* Electrons can exhibit wave-like behaviors that propagate at speeds close to the speed of light.

* When electrons change energy levels, they emit photons that travel at the speed of light.