Problem 50 - Chemistry: The Central Science

Question

If the electron affinity for an element is a negative number, does it mean that the anion of the element is more stable than the neutral atom? Explain.

Step-by-Step Solution

Answer

Yes, if the electron affinity for an element is a negative number, it means that the anion of the element is more stable than the neutral atom. This is because a negative electron affinity value indicates that energy is released during the formation of the anion, which corresponds to the stabilization of the anionic species.

Step 1: Understand electron affinity

Electron affinity is the energy change that occurs when an electron is added to a neutral atom to form a negative ion. In other words, it's the amount of energy released (exothermic process) or absorbed (endothermic process) when an electron is added to an atom. Electron affinity is usually expressed in units of kJ/mol.

Step 2: Identify the meaning of negative electron affinity

When an element has a negative electron affinity, it means that energy is released when an electron is added to the neutral atom, making the process exothermic. A negative electron affinity indicates that the negatively charged ion (anion) formed after the addition of an electron is more stable than the neutral atom because it involves a release of energy, which is associated with the formation of more stable species.

Step 3: Explain the relationship between electron affinity and anion stability

An anion is more stable than the neutral atom if its formation is accompanied by the release of energy, resulting in a negative electron affinity value for the element. This is because the electron being added to the atom can stabilize the anion by lowering its overall energy, and this stabilization is achieved through the release of energy (which corresponds to a negative electron affinity value). In conclusion, if an element has a negative electron affinity, it means that the anion of the element is indeed more stable than the neutral atom. The negative electron affinity value indicates that energy is released during the formation of the anion, and this energy release is associated with the stabilization of the anionic species.