system
Given the following post, respond as if you're commenting on Reddit:
human
Why do some materials like iron, gold and other bend, while other like coal or rocks break?
gpt
It all depends on what kind of bond and structures the atoms form. when talking about metals and rocks, crystal structures become very important. The crystal structure of a compound it decides by its composition and its preparation. Some crystal structures are very rigid and won't bend easily, other materials are actually a lot of tiny crystals that can move rather easily making the material bendy. 
This is a very complicated topic and it is hard to not go into too much detail here. The short answer is that it depends on the way the atoms are arranged in the material.