Question

24. Name the following- Alkali metal having highest melting point.

Answer 1

Step 1: Alkali metals-

• The elements placed in the first column of the periodic table are referred to as the alkali metals because when these metals react with water, they produce alkalis (basic hydroxides).
• Alkali metals include Lithium(Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).

Step 2: The trend of melting points in Alkali metals-

• The melting point depends on the forces of attraction between the nucleus and the bonding electrons, As the size of the atom increases, the distance between the nucleus and the electrons increases leading to a decrease in the forces of attraction between them. As a result, with an increase in the size of an atom of the metal, the melting point decreases.
• For alkali metals, the size of atoms increases on moving down the group, and thus melting point decreases on moving down the group.
• As Lithium is the smallest alkali metal, thus it has the highest melting point among the alkali metals.

Hence, an alkali metal that has the highest melting point is Lithium (Li).