Why do Group(||) metals have higher melting point than Group(|) metals??

Answer 1

The first two vertical columns of the Periodic Table, Groups 1 or Alkali Metals and 2or Alkaline Earth Metals, are also called the s-block metals, because they only have 1 or 2 electrons in their outer shell. These outer electrons are of an s-orbital type (s sub-shell or sub-quantum level) and the chemistry of the metals, with relatively their low ionisation energies, is dominated by the loss of these s electrons to form a cation. The outer s1 electron loss by the Group 1 Alkali Metals to gives the M+ ion and the s2 electron loss by the Group 2 Alkaline Earth Metals gives the M2+ ion. Consequently most of the compounds of Group 1-2 elements tend to be ionic in nature.

Generally (but not always), the melting and boiling points fall steadily when passing from Group 2 to Group 1. This is because the ionic radii increase down the group increasing charge separation between the metal cations of the lattice and the free delocalised electrons. This weakens the electrical attractive bonding force and so less thermal KE is needed to weaken the lattice to the 'collapse point' i.e. melting. BUT the situation is not as simple as might be expected, e.g. the metal ions do not always have the same crystal lattice packing arrangement.

Answer 2

Group I metals give 1 electron from each to form metallic bonds
But Group II metals give 2 electron from each to form metallic bonds
Therefore, Group(||) metals have higher metallic bonds than Group(|) metals.
Ultimately, Group(II) metals need more energy than Group (I) metals need, to break metallic bonds and then melt.

Answer 3

Stronger covalent bonding.