The first ionization energy of mercury is 1006 kJ/mol. The energy change for the reaction Hg(l) $\rarr$Hg⁺(g) + e^- is therefore A) 1006 kJ/mol. B) greater than 1006 kJ/mol. C) less than 1006 kJ/mol. D) is equal to the electron affinity of mercury. E) is equal to the second ionization energy of mercury.

Question

Quizplus · Accepted Answer

The reaction given is the first ionization energy for mercury, which is the energy required to remove one electron from a neutral mercury atom in the gas phase. The products of the reaction obtained by removing one electron from Hg are HgS and an electron. The energy change associated with this reaction is equal to the first ionization energy of mercury, which is 1006 kJ/mol. Therefore, the answer is not A.

Since one electron is being removed from an atom, the energy required to remove it should be less than the energy released by forming a bond between Hg and S. Therefore, the energy change for the reaction is expected to be less than the first ionization energy of mercury, meaning the answer is not C.

The answer is also not D or E. Electron affinity is the energy change that occurs when a neutral atom gains an electron to form an anion. It is a completely different process than ionization energy, which describes the energy required to remove an electron from an atom. The second ionization energy of mercury is the energy required to remove a second electron from a Hg+ ion, which is not related to the given reaction.

Thus, the only valid choice is B.

The First Ionization Energy of Mercury Is 1006 KJ/mol →\rarr→ Hg+(g) + E- Is Therefore A) 1006 KJ/mol

The First Ionization Energy of Mercury Is 1006 KJ/mol $\rarr$ Hg⁺(g) + E^- Is Therefore
A) 1006 KJ/mol