When is less energy required to move a valence electron?

Less energy is required to move a valence electron when it is in an atom with a larger atomic radius, as the valence electrons are farther from the nucleus and experience weaker electrostatic attraction. Additionally, in elements with lower electronegativity or ionization energy, the valence electrons are more easily removed. This is typically observed in alkali metals, where the single valence electron is loosely held and can be removed with minimal energy input.