What is valence electron? September 24, 2024 by Author The electrons at the outermost principal energy level of an element are called the valence electrons of that element. Related Posts:Atom Definition, What is atom? How big is an atom?Basis of Periodic TableWhat is periodicity? What causes the periodicity in…What is ionization energy?Lessons on LifeStephen Curry: The Unstoppable Force in Basketball