The atomic number of an element is the number of protons in the nucleus of its atom. The number of electrons in orbit around the nucleus of a neutral atom is equal to the number of protons in the nucleus. The valence of an element is the number of electrons in the outermost orbit. An electric circuit is a closed path for electron flow. Potential difference must be applied to a circuit to produce electron current flow.
Electrons flow through an external circuit from negative to positive.