Answer:
The collision theory states that a chemical reaction can only occur between particles when they collide (hit each other).
<em>h</em><em>o</em><em>p</em><em>e</em><em> </em><em>i</em><em>t</em><em> </em><em>h</em><em>e</em><em>l</em><em>p</em><em>s</em><em>~</em>
The smallest unit that can exist as an element and still have proprieties of that element is an Atom<span />
