There are not two main types of electrons. Electrons are fundamental particles, meaning they are not made up of smaller parts. All electrons are identical, with the same mass, charge, and other properties.

However, electrons can be described in different states depending on their energy level and location within an atom:

1. Bound Electrons: These electrons are associated with an atom and are bound to its nucleus by electrostatic attraction. They exist in specific energy levels, called orbitals, which determine their behavior and contribute to the atom's chemical properties.

2. Free Electrons: These electrons are not bound to any particular atom and can move freely within a material. They are responsible for electrical conductivity in metals and semiconductors.

Here's how they differ:

| Feature | Bound Electrons | Free Electrons |

|--------------|------------------------------------------------------|----------------------------------------------------------|

| Location | Orbiting the nucleus of an atom | Moving freely within a material |

| Energy Level| Exist in specific, quantized energy levels | Can possess a range of energy levels |

| Movement | Restricted to their orbital | Can move throughout the material, even against an electric field |

| Role | Determine the atom's chemical properties | Contribute to electrical conductivity |

So, while there's only one type of electron, its behavior and role can change depending on its state within a material.