Respuesta :
Answer: The fraction of atom's mass contributed by nucleus is 0.99
Explanation:
Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.
The isotopic symbol of Helium-4 atom is [tex]_2^4\textrm{He}[/tex]
Number of electrons = 2
Number of protons = 2
Number of neutrons = 4 - 2 = 2
We are given:
Mass of He-4 atom = [tex]6.64648\times 10^{-24}g[/tex]
Mass of 1 electron = [tex]9.10939\times 10^{-28}g[/tex]
Calculating the mass contributed by the nucleus = [tex]m_{He}-2(m_e)[/tex]
Mass of the nucleus of He-4 atom = [tex]6.64648\times 10^{-24}-(2\times (9.10939\times 10^{-28}))=(6.64648-0.0018219)\times 10^{-24}=6.64466\times 10^{-24}[/tex]
To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:
[tex]\text{Fraction of atom's mass contributed by nucleus}=\frac{\text{Mass of nucleus}}{\text{Mass of atom}}[/tex]
Putting values in above equation, we get:
[tex]\text{Fraction of atom's mass contributed by nucleus}=\frac{6.64466\times 10^{-24}g}{6.64648\times 10^{-24}g}=0.99[/tex]
Hence, the fraction of atom's mass contributed by nucleus is 0.99
