Why is the charge transmitted by electrons and not protons?

Can I expect the answer from engineers who are crazy ?😀

Protons are bound inside the nucleus not really able to move. If you want them out, that's like breaking the nucleus which would generate a lot of energy. Oh yeah, you know what that is called right, splitting the nucleus to lighter nuclei.

That leave us with electrons which are that can be easily made to jump out from the binding forces with quite less energy. In the case of metals, there already are a lot of free electrons. All that is needed is the application of a potential difference to make them move. Well that's a fairly vague explanation, yet.

where the NUCLEUS go ? will it stay in that structure ?

N.SACHIN

where the NUCLEUS go ? will it stay in that structure ?

Definitely. Nucleus will stay where it is, still surrounded by the electrons. Not all electrons of an atom are free. In fact, its the force from the nucleus which prevents the electrons from getting free. So the farther is the electron, the lesser is the influence of nucleus and the more they are likely to get free with minimal excitation.

Is there any impact on the nucleus by potential difference ? If so how the nucleus reacts ?

What i have understood by viewing your question is that you want to know what is the fate of nuclei when electron flows through a circuit, right?
Generally as we all suppose an atom consists of two portions -the nucleus and another one is the extra nuclear part.The nucleus consists of protons and neutrons whereas the extra nuclear part contains the free electrons. Now if an atom is in stable state and if you provide voltage difference to it, it just makes no sense as the system is already stable and why it will require that energy? In case of conductors and semiconductor devices of which electronic circuits are generally made of ,applying a voltage difference causes formation of energy distribution across these devices that results the flow of electrons which are mobile enough and much lighter than the nucleus and are loosely bound with the atom. An atom looses an electron and a same time an electron joins it and this transfer of electrons from one atom to another atom results in the flow of a directional scalar electric current across the conductors.The atoms doesn't move and hence the nuclei associated with the atom also stays as it is maintaining the lattice structure of the material. To move an atom and hence the nuclei from an element requires that element to undergo a chemical change where the property of the material doesn't remains the same.That kind of changes hardly occur when electric current flows through a conductor. In cases of nuclear reactions you can notice the change in the nuclei of an element where a new element with different nuclei structure is generated.

The protons and neutrons are extremely tightly bound to the nucleus by means of the strongest of the four fundamental forces, the strong interaction, which has appreciable effects at the nuclear level only. By applying an electric field or pd across a conductor, the electromagnetic interaction comes into the picture. This has a magnitude incredibly lower than the nuclear force binding the nucleons together and hence, it is impossible to displace the nucleons. When we apply a pd, the free electrons in a conductor move at the drift velocity and conduction takes place. However, as mentioned above in Alpha decay, the nucleons are ejected owing to an interplay between the strong and electromagnetic interactions.