Answer :
Answer:
"Collide" completes the sentence.
Explanation:
In chemistry and physics, the term "collide" refers to the interaction or contact between particles that is necessary for a reaction to occur. This collision can lead to chemical reactions, changes in energy levels, or other transformative processes depending on the nature of the particles involved.
The word that completes the sentence is “collide”. So the full sentence would be: “For a reaction to happen the reacting particles must successfully collide with one another.” This concept is a key part of the Collision Theory in chemistry, which states that for a chemical reaction to occur, the reacting particles must collide with sufficient energy and the proper orientation.
