The statement "The valence electrons are easily delocalized" best describes the effect of low ionization energies and low electronegativities on metallic bonding. Electronegativity is defined as the atom's ability to attract electrons. In a metallic bond the positive nucleus is surrounded by electrons that are free to move. This delocalized electrons create electrostatic interaction between positive and negative charge, which keeps the metal together. Delocalization makes it difficult for the nucleus to attract electrons towards itself hence low ionization energy and low electronegativity.
