Scientists developed symbols and gave the elements numbers to help organize the elements by their chemical properties. The periodic table helps identify the underlying chemical and physical traits of the elements.
Answer:
In a chemical reaction, reactants that are not used up when the reaction is finished are called excess reagents. The reagent that is completely used up or reacted is called the limiting reagent, because its quantity limits the amount of products formed.
Explanation:
Bromine has 35 protons, and in this case 46 neutrons, so 35 + 46 = 81
Therefore, the symbol is (subscript 35)(superscript 81) Br.