Well one answer would be metal
Answer:
Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. Molecules must collide with the proper orientation. A collision that meets these two criteria, and that results in a chemical reaction, is known as a successful collision or an effective collision.
Answer: 
Explanation:
Neutralization is a chemical reaction in which acid and base combine to form salt and water. Acids donate 
ions and bases donate 
ions in water which combine to form water molecules.
The balanced molecular equation is ;
Answer:
Isotopes
Explanation:
This is the definition of isotopes: they are atoms of the same element that contain different numbers of neutrons.
