What are two types of pure substances ? what is the difference between the two ?

The main difference between an element and a compound is that an element is made up of the same type of atom throughout while a compound is composed of multiple different elements. Both are pure chemical substances found in nature.

nanotechnology is a powerful tool in biomaterials research as it creates numerous possibilities for the engineering of functional molecules. nano-bio refers to projected ability to incorporate biomimicry into various materials at nanoscale.  

14,16 18 reacts with group