Question

Name the members of alkali metal group which has the :

Highest melting point.

Answer 1

The Alkali metal group is group 1 of the periodic table which has the following elements:

Hydrogen (H)

Lithium (Li)

Sodium (Na)

Potassium (K)

Rubidium (Rb)

Cesium (Cs)

Francium (Fr)

The melting point is the temperature at which the substance changes its state from solid to liquid.

The melting point depends on the intermolecular force between the different atoms.

Periodic trend:

The melting point generally decreases down the group due to an increase in the size of the atom. As the size of atom increases, the intermolecular bonding between the atoms decreases.

The melting point of Lithium is$180.5^{0}C$, sodium is$97.{79}^{0}C$, Potassium is $63.5^{0}C$, Rubidium is $39.5^{0}C$, Cesium is $28.5^{0}C$ and Francium is ${27}^{0}C$.

Hence, Lithium has the highest melting point in group 1.