Explain isobars with a suitable example.
b) Give one use of each of the following: 1) lodine-131 i) Cobalt-60
c) Bromine has two isotopes Br(49.7%) and Br(50.3%) Calculate the average atom
bromine atom correct to two decimal places.
31. a) Expand CFC
e the average atomic mass of
Answers
Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. Correspondingly, isobars differ in atomic number (or number of protons) but have the same mass number. An example of a series of isobars would be 40S, 40Cl, 40Ar, 40K, and 40Ca.
1. Iodine-131
It is used in medical field, to diagnose and treat thyroid gland disorders.
2. Cobalt-60
It is used in medical field, for cancer treatment.
Average atomic mass of an element is calculated by taking the weighted average of the atomic masses of stable Isotopes.
In this case , as we know Bromine has two stable Isotopes, Bromine-79 and Bromine -81.
The isotope with mass 79 is present in 49.7% and isotope with mass 81 is present in 50.3% in nature.
Therefore Average atomic mass of bromine is:
= ( 79x49.7/100) +(81x50.3/100)
=(79x0.497) + (81×0.503)
=39.264 + 50.743
=80.006u
Chlorofluorocarbons
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