Question

Why alkali metals are soft and have low melting and boiling point?

Answer 1

All alkali metals are very soft and they have all low melting/boiling points. Alkali metals have only one valence electron and so have low binding energy to the metallic crystal lattice. ... A lower amount of energy needed to break a bond means a lower melting/boiling point.

Answer 2

Alkali metals have very low ionization enthalpy because of there small size . therefore there bond dissociation enthalphy is very low in a crystal