What do an electron and a neutron have in common?

Each particle has a mass of 1 amu.

Each particle exists inside an atom.

Each particle has an electrical charge.

Each particle is located in the nucleus.

Each particle exists inside an atom.

Neutron has a mass of 1 and no charge whereas electron has negligible mass but a charge of - 1. Thus the only thing that they have in common is that both exist in an atom.