How does the electronegativity trend explain the first ionization energy trend

Electronegativity is the ability of an atom to attract a bonding pair of electrons. Electronegativity decreases down a group. The number of shell increases down a group, this means that down a group, the outermost electrons become further and further away from the nucleus, decreasing their attraction for the nucleus and therefore decreasing their ability to attract a bonding pair of electrons.