Here's why:

* Malleability refers to a material's ability to be hammered or rolled into thin sheets without breaking. This property is primarily associated with metals due to their atomic structure.

* Helium, like other noble gases, exists as individual atoms that are not bonded together. It's a gas at room temperature and has a very weak interatomic force.

* Because helium atoms are not connected in a solid structure, they cannot be deformed or shaped like metals.

Instead of malleability, helium exhibits properties like:

* Low density: Helium is the lightest element and has a very low density.

* Inertness: It does not readily react with other elements due to its full outer electron shell.

* Thermal conductivity: It is an excellent conductor of heat.

So, while helium is not malleable, it has other unique and useful properties.