CAIE A-Level Chemistry 1.1.6 Numbers of Protons, Neutrons and Electrons
Practise determining proton, neutron and electron counts in atoms and ions from nuclide notation and charge.
- Syllabus
- 2028–2030
- Course
- Chemistry 9701
- Level
- AS
Practise determining proton, neutron and electron counts in atoms and ions from nuclide notation and charge.
All the Group 2 elements except beryllium have more than one stable isotope.
Complete Table 2.2 to show the numbers of protons and neutrons in the isotopes of magnesium.

Table 2.2
isotope & number of protons & number of neutrons
magnesium-24 & 12 & 12
magnesium-25 & 12 & 13
magnesium-26 & 12 & 14