Identify the incorrect statements.

1. Alkaline earth metals have stronger metallic bonding than the corresponding alkali metals.
2. Alkaline earth metals have higher densities than corresponding alkali metals.
3. Melting points in alkaline earth metals are lower than for the corresponding alkali metals.
4. Alkaline earth metal carbonates higher thermal stability than corresponding alkali metal carbonates.

Because their atoms are significantly smaller than those of alkali metals, alkaline earth metals have higher densities. Alkaline earth metal ions are much smaller in size than corresponding alkali metal ions and carry a higher charge. Thus, their polarizing power is greater. Electron cloud of carbonate anions are more easily distorted by alkaline earth metal ions than by alkali metal ions. Therefore, alkaline earth metal carbonates are less stable to heat and decompose to form metal oxide and carbon dioxide. Thus, this option is wrong. This option is correct because melting points in alkaline earth metals are higher than for the corresponding alkali metals. Alkaline-earth metals contribute two electrons per atom to the mobile electron cloud whereas alkali metals contribute only one electron per atom. The greater number of electrons and the smaller ionic size of the alkaline earth metals helps to increase the density of the electron cloud and thus increase the attractive forces between the mobile electrons and the cationic lattice. Alkaline earth metal ions are much smaller in size than corresponding alkali metal ions and carry a higher charge. Thus, their polarizing power is greater. Electron cloud of carbonate anions are more easily distorted by alkaline earth metal ions than by alkali metal ions. Therefore, alkaline earth metal carbonates are less stable to heat and decompose to form metal oxide and carbon dioxide.