Chapter EH, Problem 15R

Solution

Interpretation : The physical properties of the alkaline earth metals and the alkali metals are to be compared.

Concept Introduction : Alkali metals are the elements belonging to group 1 and alkaline earth metals are the elements belonging to group 2.

Both alkaline earth metals and alkali metals are metallic and silvery in appearance. Their densities rise down the group while the melting point and boiling point decrease down the group.

Alkaline earth metals are hard, but alkali metals are soft in nature.

Most alkaline earth metals seem metallic and silvery-white.

Though these metals are stronger, dense, and harder than alkali metals, they are soft in comparison with the other metals.

Most alkaline earth metals have higher melting points and boiling points than alkali metals.

When exposed to oxygen, a thin oxide coating forms on the surface.

In general, densities rise as one moves down the group.

Pure alkali metals have a metallic, silvery appearance.

Alkali metals are soft in nature

When compared to the solid forms of elements from other groups, most alkali metals have low densities.

Metals such as potassium, sodium, and lithium have a lower density than water.

Alkali metals have lower melting points than other metals like silver or gold.