Alkali metal/Properties

Material==> Property V	Lithium	Sodium	Potassium	Rubidium	Caesium	Francium
Electronegativity	0.98	0.93	0.82	0.82	0.79	0.7
Melting point	180.5 °C	97.8 °C	63.5 °C	39.3 °C	28.5 °C	27 °C
Boiling point	1342 °C	883 °C	759 °C	688 °C	671 °C	677 °C

Low ionization energies result in Alkali metals having metallic properties and relatively high reactivities.