Considering the definition of atomic mass, isotopes and atomic mass of an element, the % composition of each isotope is:
First of all, the atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.
The same chemical element can be made up of different atoms, that is, their atomic numbers are the same, but the number of neutrons is different. These atoms are called isotopes of the element.
On the other hand, the atomic mass of an element is the weighted average mass of its natural isotopes. In other words, the atomic masses of chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element, taking into account the relative abundance of each of them.
In this case, the first isotope Gallium - 69 has an atomic mass of 69 and a percent natural abundance of X%. The second isotope Gallium - 71 has an atomic mass of 71 and a percent natural abundance of (100-X)%.
On the other hand, the Relative Atomic Mass of Gallium is 69.8 .
Then, the value of X can be calculated as:
69× X+ 71× (1-X)= 69.8
Solving
69× X+ 71× 1- 71× X= 69.8
69× X+ 71- 71× X= 69.8
69× X- 71× X= 69.8 - 71
- 2× X= -1.2
X= (-1.2)÷ (-2)
X=0.6 which expressed as a percentage is X%= 60%.
So, the % compositon of Gallium - 71 is calculated as (100-X)%=(100 -60)%= 40%
Finally, the % composition of each isotope is:
Learn more about average atomic mass:
brainly.com/question/4923781
brainly.com/question/1826476
brainly.com/question/15230683
brainly.com/question/7955048
#SPJ1
