The graph below shows the relative quantities of energy equivalent to successive ionisation energies for an element - Scottish Highers Chemistry - Question 2 - 2022

To determine the most stable ion from the element shown in the graph, we first analyze the pattern of ionization energies. The significant increase in ionization energy after the 2nd ionization indicates that the third electron is much harder to remove than the second. This suggests that after losing two electrons, the element achieves a stable electron configuration.

Since it takes much more energy to remove the third electron, it is reasonable to conclude that the most stable ion is formed after the loss of two electrons, leading us to select the option with a charge of 2+, which corresponds to option A.