[Needaask]

The metallic bond is between the cation of the nucleus and the valence electrons. So how does that give it that orderly shape and high melting/boiling temperature?

My idea is that the two nucleus would repel each other greatly but they are both attracted to the common valence electrons so they have an orderly shape. And when we heat up the metal, the bond between the cation and valence electrons is weakened so now the electrons are further away from the two nuclei so the two nucleus repel each other more greatly. So when we reach Tm the repulsion outweighs the attraction as the valence electrons are too far from the nucleus so they melt. is this correct?

[Arkcon]

The metallic bond is between the cation of the nucleus and the valence electrons.

This wikipedia article here:  http://en.wikipedia.org/wiki/Metallic_bond highlights how that is a simplistic definition, that causes problems just like you mentioned.  It is more correct to say that the electrons are shared in a sort of broadly delocalized resonance structure.  Something like benzene's structure.  There's more in that article.  In particular, your model doesn't take in to account low melting point metals -- like zinc, cadmium, mercury and gallium.  And doesn't account for the very high boiling point of metals -- including zinc, cadmium, mercury and gallium.