The smallest particle that exists in this world  
the basic building blocks of matter
please mark my answer as best
the smallest particle of an element is called atom
The Brainliest Answer!
Atom it is the smallest piece of the given substance that can exist

example : if your going on cutting a piece of wood and you came to a point where you cant cut it any more that piece is called a atom of the given substance.
hope so answer is useful and help full
1 5 1
if you like my answer plz mark it as best plz plz ^_^