Which statement best describes the effect of low ionization energies and low electronegativities on metallic bonding?
the valence electrons are easily delocalized.
the valence electrons stay in a single orbital.
the valence electrons break free of the crystals.
the valence electrons move closer to the nuclei.

The statement that best describes the effect of low ionization energies and low electronegativities on metallic bonding is the first one - the valence electrons are easily delocalized. 
Due to these low energies and negativities, valence electrons can be moved around quite easily and their positions may be altered quite drastically.