The outermost electron in lithium orbits at roughly the Bohr radius, Because the two internal electrons decrease the nuclear cost by 2. This outer electron need to be at practically one Bohr radius through the nucleus. Since the electrons strongly repel one another, the effective cost description is quite approximate; https://digitalesmagazinz.de/warum-jedes-unternehmen-in-eine-hochwertige-sackkarre-investieren-sollte/