Answer:
263.1 is exactly three half-life, so the remaining portion is (1/2 x 1/2 x 1/2) of the original sample. That's 1/8 which is 12.5%
Stoichiometry is the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers. Hoped this helped!!!!. Also if you are trying to look for the formulas it should be online just type in stoichometry formulas.
Answer
im not quite sure but I think the answer is <em>D atom</em><em> </em>
Explaination
