Good job for trying though :)
No, neutrons are not the opposite of electrons. They are subatomic particles, therefore they are matter, so their opposite is antimatter (completely theoretical by the way). If you were looking at charges, the subatonic particle with the opposite charge of an electron would be a proton. Neutrons don't have charges, so they can't have opposites by charge in the same way that there is no opposite of zero, there's no opposite of "no charge".