* Physical Changes: These changes alter the form or appearance of a substance but don't change its chemical composition.

* Melting (and freezing) are examples of physical changes. The sodium atoms are still sodium atoms, just arranged differently.

* Chemical Changes: These changes result in the formation of new substances with different chemical compositions.

* Examples include burning wood, rusting iron, or baking a cake.

In the case of melting sodium:

* The sodium atoms are simply moving more freely, changing from a solid to a liquid state.

* The chemical composition of the sodium remains the same (it's still sodium).

Therefore, the melting point of sodium is a physical property.