Question

Why some metals are soft?

Answer 1

Soft Metals have the higher atomic radius and they also loosely bound electrons in their outer orbital shell.

• The attraction between the Nucleus and outer orbital is not that much so it can be bounded tightly.
• To understand it better, let us take the example of Sodium.
• Sodium being a metal, consists of Na+ ions surrounded by a sea of electrons (as per the free electron theory).
• Sodium is a member of alkali metals i.e. has a large size compared to the other group elements.
• Thus the nuclear charge of the Na+ ions is low, leading to a poor interaction force between the metal ions and the electrons.
• Hence application of a small force can break the lattice, making sodium soft.