Sodium is a metal that can be easily cut with a knife.

Explanation:
Sodium belongs to the alkali metal group (Group 1) of the periodic table. As we move down the alkali metal group, the atomic size increases, resulting in a decrease in the force of attraction between the valence electron and the nucleus. This leads to weaker metallic bonds and lower hardness in alkali metals like sodium. Due to its soft and malleable nature, sodium can be easily cut with a knife or even a sharp object.