For example hydrogen has one proton, carbon has six and plutonium has 94. It is very difficult to remove protons from the nucleus but it is relatively easy to remove at least some of the electrons. This gives us a clue as to why some materials are good conductors whilst others are poor. In conductors electrons are fairly free to move and so we can have flow of electrical charge. Again this gives us a further clue.
Electrical current is the rate of flow of electric charge.
We need to study a little chemistry here. We are all familiar with sodium chloride or common salt. Sodium chloride is formed by the combination of sodium and chlorine. So we have sodium ions which are positively charged and chloride ions which are negatively charged. In this solid the attraction between the sodium ions and the chloride ions is strong and it is difficult to separate them.