Materials that allow electrons to move easily from atom to atom are called conductors.

Here's why:

* Conductors have a structure where electrons are loosely bound to their atoms. This means they can easily break free from their atoms and move throughout the material.

* Insulators, on the other hand, hold their electrons tightly, making it difficult for electrons to move freely.

Examples of good conductors include:

* Metals (like copper, silver, gold)

* Graphite (a form of carbon)

* Some solutions with dissolved salts (electrolytes)

Let me know if you'd like to explore conductors and insulators in more detail!