Are some metals soft, and volatile?

Metals are NON-molecular materials. And the typical view of metals is #"as positive ions in a sea of electrons"#. What does this mean? It means that each metal ATOM, contributes one or two or three electrons to the metallic lattice. These electrons are conceived to the be delocalized over the entire metallic lattice, and the metal nuclei, the positive metal ions, that result can move with respect to each other.

This view of metallic bonding rationalizes the physical properties of metals: (i) their #"malleability"#, their ability to be hammered out into a sheet; (ii) their #"ductility"#, their ability to be drawn out into a wire; and (iii) their #"conductivity"# towards heat and electricity. Because the metallic bond is fairly fluid, and there are delocalized electrons in the lattice, these electrons are presumed to account for these properties.

But look at some metals, for instance the alkali metals. These metals are SOFT, and exhibit very low melting and boiling points, especially for non-molecular materials. Mercury metal is even a LIQUID (one of the few elemental liquids).

Metals with several valence electrons TEND to be strong, high melting point materials. For instance iron, which as steel is the premier building material.

The diagram (if I have inserted it right!) depicts the electronic delocalization.