The Nuclear Atom · Paper 1 — Free Chemistry SL Practice Questions

A mass spectrum of naturally occurring magnesium shows three peaks at $m/z = 24$, $25$, and $26$ with relative abundances of 79%, 10%, and 11% respectively. The atomic number of magnesium is 12. How many neutrons are present in the most abundant isotope of magnesium?

Two samples of element X are analysed. Atoms in the first sample contain 17 protons, 18 neutrons, and 17 electrons. Atoms in the second sample contain 17 protons, 20 neutrons, and 17 electrons. Which statement correctly describes the relationship between these two samples?

A mass spectrum of neon shows peaks at mass numbers 20, 21, and 22 with relative abundances of 90.5%, 0.3%, and 9.2% respectively. The atomic number of neon is 10. How many neutrons are present in the $^{22}$Ne isotope?

In the mass spectrum of naturally occurring chlorine, peaks appear at $m/z = 35$ and $m/z = 37$ with relative abundances of 75.8% and 24.2% respectively. For the isotope responsible for the peak at $m/z = 37$, a student correctly determines that the nucleus contains 20 neutrons. How many protons does this isotope contain?