Three isotopes of silicon have mass numbers of 28,29, and 30 with an average atomic mass of 28.086 what does this say about the relative abundances of the isotopes

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Chemistry

Drew Todd

4 June, 07:34

Three isotopes of silicon have mass numbers of 28,29, and 30 with an average atomic mass of 28.086 what does this say about the relative abundances of the isotopes

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Elizabeth Richard · Answer 1

Answer is: silicon isotope with mass number 28 has highest relative abundance, this isotope is the most common of these three isotopes.

Ar₁ (Si) = 28; the average atomic mass of isotope ²⁸Si.

Ar₂ (Si) = 29; the average atomic mass of isotope ²⁹Si.

Ar₃ (Si) = 30; the average atomic mass of isotope ³⁰Si.

Silicon (Si) is composed of three stable isotopes, ₂₈Si (92.23%), ₂₉Si (4.67%) and ₃₀Si (3.10%).

ω₁ (Si) = 92.23%; mass percentage of isotope ²⁸Si.

ω₂ (Si) = 4.67%; mass percentage of isotope ²⁹Si.

ω₃ (Si) = 3.10%; mass percentage of isotope ³⁰Si.

Ar (Si) = 28.086 amu; average atomic mass of silicon.

Ar (Si) = Ar₁ (Si) · ω₁ (B) + Ar₂ (Si) · ω₂ (Si) + Ar₃ (Si) · ω₃ (Si).

28,086 = 28 · 0.9223 + 29 · 0.0467 + 30 · 0.031.