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A sample of chlorine is modelled as containing only the two isotopes shown in Figure 1. Use the mass numbers as the isotope masses when calculating the relative atomic mass.
State the number of neutrons in
State where the electrons are found relative to the nucleus in a chlorine atom.
Explain why and are isotopes.
Using Figure 1, determine the relative atomic mass of the chlorine sample. Give your answer to 3 significant figures.
An enriched copper sample contains only and Treating the mass numbers as isotope masses, its relative atomic mass is 63.60. Which description gives both their abundances in the sample and the subatomic-particle counts in the corresponding ions?
Answer: B. The abundance-weighted mean gives so the fraction of is Both isotopes have 29 protons; their neutron numbers are and Each ion has lost two electrons, leaving 27.
A: reverses the abundances, which would give a mean mass of 64.40.
C: treats the charge as two extra electrons rather than two fewer.
D: reverses the subtraction for neutron number, assigning more neutrons to the lower-mass isotope.
Remember: Isotopes differ in neutron number; ion charge reflects electron gain or loss.
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