Which element in group 1 has the greatest tendency to lose an electron

Fr has the greatest tendency to lose an electron. Electronegativity, which is an elements tendency to gain an electron, decreases as you go down a group, meaning that an element’s tendency to lose an electron increases as you go down a group. This means that the element in group 1 with the lowest electronegativity (the element at the bottom of the group), Fr, the element with the greatest tendency to lose an electron.

Both models are effective because they show the valence electrons, and these valence electrons indicate the reactivity of an element.