The average atomic mass of an element can be determined by multiplying the individual masses of the isotopes with their respective relative abundances, and adding them.
Average atomic mass of Br = 158 amu(0.2569) + 160 amu(0.4999) + 162 amu(0.2431)
Average atomic mass = 159.96 amu
As described in the problem, the relative abundance for Br-79 is 25.69%. This is because 2 atoms of Br is equal to 79*2 = 158 amu. Similarly, the relative abundance of Br-81 is 81*2 = 162, which is 24.31%.
It can take 49 days, I could be wrong. What do you mean in this question?
Answer:
1st question: The moon is closer to Earth so it is easier to see and visit.
2nd question: The moon has a week/month cycle instead of a day/night cycle.
3rd question: The corona
Explanation:
The purpose is that it shows you all the elements we know and it arranges them in groups that are also the same kind like Chemistry.
