The measure of how easily a mineral can be scratched is called hardness. And you are absolutely right, it is determined by the arrangement of the mineral's atoms.

Here's why:

* Atomic Bonds: The strength of the bonds between atoms in a mineral determines how resistant it is to being scratched.

* Crystal Structure: The arrangement of atoms in a mineral's crystal lattice (its repeating pattern) influences the strength and direction of these bonds.

Example:

* Diamond: Has a very strong, tightly packed, three-dimensional structure with strong covalent bonds. This makes it the hardest known natural mineral.

* Talc: Has a layered structure with weak bonds between the layers. This makes it very soft, easy to scratch, and even feels slippery to the touch.

Mohs Hardness Scale:

To measure hardness, we use the Mohs Hardness Scale. This scale ranks minerals from 1 (softest) to 10 (hardest) based on their ability to scratch or be scratched by other minerals.

Let me know if you'd like to know more about the Mohs scale or any specific mineral's hardness!