There are TWO isotopes of chlorine. Under normal conditions, chlorine exists as diatomic molecule, Cl₂. The mass of the Cl₂ mole
cule is the sum of masses of the two atoms in the molecule. The mass spectrum of Cl₂ has three peaks, as shown below. From this data, what is the mass of the heavier isotope of chlorine (in amu)? Peak 1- 69.938 amu
Peak 2- 71.935 amu
Peak 3- 73.932 amu
The the mass of the heavier isotope of chlorine (in amu) is 73.932 amu.
<h3>What are isotopes?</h3>
The term isotopes refers atoms that have the same atomic number but different mass number. We must know that all these atoms belong to the same element an differ only in the number of neutrons present in the atom of the element. Hence isotopes are different atoms of the same element hence they have the same chemical properties or reactivity. The mass spectrum is able to show the masses of each of the isotopes according to their order of relative abundance in nature.
Looking at the peaks, we know that the heaviest isotope is the one whose mass will have the highest peak as shown in the mass spectrum of the element as shown. Thus, the the mass of the heavier isotope of chlorine (in amu) is 73.932 amu. The mass spectrum of element also shows this fact.