CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
When a cation is further ionized, an electron is removed from an already positively charged species. Consider the following two successive ionizations carried out in the gas phase at the same temperature:
(i) Na+→ Na2++e−
(ii) Mg+→ Mg2++e−
Both Na and Mg are in Period 3.
(a) Predict which step, (i) or (ii), requires a greater amount of energy. State your choice clearly.
(b) Justify your prediction by analyzing subshell occupation, electron–electron repulsions, and any changes in effective nuclear charge between the two processes.
(c) Explain why the trend you described in part (a) may not be identical to the trend in first ionization energies for neutral Na versus neutral Mg.
(d) Suppose Na2+ were to regain an electron to return to Na+. Would the magnitude of the energy released be exactly equal to the energy absorbed in step (i)? Discuss, citing one or more factors that could make the numerical values differ.