You are made up of many elements. Oxygen, Water, etc.
A substance that only contains one kind of atom is called an element.
That would be radioactive decay.
mercury
An atom is the smallest piece of an element that can be identified as that element.
how do you find an element's group
what kind of question are that?
atom
diatomic
nonmetal
a metal
no it is not
Every element has its own kind of atom, identifiable from atoms of another element by its number of protons.