Explanation:
The more reactive element replaces less reactive element during chemical reaction.
Since, potassium is more reactive than beryllium. When potassium reacts with beryllium choride, it replaces beryllium and forms potassium chloride and produces beryllium.
Answer:
If your asking why they are different because atoms are rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both reactants and products for them to be the same.
