The element with the lowest electronegativity would typically be an element with a small number of valence electrons and a large atomic radius.
Elements with few valence electrons (like alkali metals) tend to have lower electronegativity because they are more willing to lose their electrons and form positive ions. Additionally, a large atomic radius means that the nucleus is further away from the valence electrons, which decreases the nucleus's pull on the electrons of other atoms, leading to lower electronegativity.