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Strontium has four isotopes. Strontium-84 has a very low natural abundance but^8

ID: 530982 • Letter: S

Question

Strontium has four isotopes. Strontium-84 has a very low natural abundance but^86 Sr, ^88 Sr, and^88 Sr are all reasonably abundant. Knowing the atomic weight of strontium is 87.62, which of the more abundant isotopes predominates? Strontium-87 Strontium-88 Strontium-86 Chlorine has two isotopes. Both^35 Cl and^37 Cl are reasonably abundant. Knowing the atomic weight of chlorine is 35.45, which of the isotopes predominates? Chlorine-37 Chlorine-35 Boron has two isotopes. Both^10 B and^11 B are reasonably abundant. Knowing the atomic weight of boron is 10.81, which of the isotopes predommates? Boron-11 Boron-10

Explanation / Answer

Ans . Always remember that the standard mass of an element is closest to the highest percentage abundance isotope.

a) b) strontium - 88

The standard mass 87. 62 amu is closest to Sr- 88 isotope , so this must be the most abundant isotope.

b) b) chlorine - 35

Again the standard atomic mass of chlorine is 35.45 amu which is closest to chlorine -35 , hence it is the most abundant isotope that predominates.

c) a) Boron 11

As the standard atomic mass of Boron is 10.81 amu , which is closest to boron -11 isotope, so the boron-11 isotope predominates