What is the definition of electricity in terms of electron flow?

The definition of electricity, particularly when discussing its behavior in conductive materials, is best described as the flow of valence electrons. Valence electrons are the electrons in the outermost shell of an atom that are involved in chemical bonding and can move freely in conductive materials like metals. This movement of valence electrons constitutes the flow of electric current, which is the basis of how electricity operates in circuits.

Other options refer to different concepts that do not accurately define electricity. The movement of protons, for instance, does not occur in a conductive material in a way that creates electric current, as protons are housed in the atomic nucleus and do not move freely. Static charge refers to an imbalance of electric charge, which is a separate phenomenon from the continuous flow of electricity. Lastly, the reaction of atoms involves chemical changes but does not directly pertain to the flow of electrical current. Therefore, the most accurate understanding of electricity in terms of electron flow focuses specifically on the movement of valence electrons.