Problem 52 - 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

A negative electron affinity for an element generally indicates that its anion is more stable than its neutral atom, as energy is released when an electron is added to the atom. This suggests the atom has a tendency to attract electrons and form anions, often resulting in a stable electron configuration. However, other factors such as electrostatic repulsion between electrons also influence anion stability, so electron affinity alone does not solely determine anion stability.

Step 1: Understanding Electron Affinity

Electron affinity is defined as the amount of energy released or absorbed when an electron is added to a neutral atom to form a negative ion (anion). A more negative electron affinity indicates that an atom has a greater tendency to gain an electron and form an anion. In general, atoms with high electron affinity have high electronegativity and are more likely to form anions because they can easily attract electrons from other atoms.

Step 2: Stability of Anions and Neutral Atoms

The stability of an anion depends on the balance between the energy released by the electron affinity and the energy needed to overcome the electrostatic repulsion between the outer electrons. When an electron is added to an atom, there is an attraction between the positively charged nucleus and the negatively charged electron. If the energy released through electron affinity is greater than the energy required to overcome the repulsion between the electrons, the anion will be stable.

Step 3: Negative Electron Affinity and Anion Stability

If the electron affinity for an element is negative, it means that energy is released when an electron is added to the neutral atom to form an anion. In general, the more negative the electron affinity, the more stable the anion is. This is because a negative electron affinity indicates that the atom has a tendency to attract electrons and form anions, which usually results in a more stable electron configuration for the atom. However, it is important to note that electron affinity alone does not solely determine the stability of an anion. Other factors, such as the electrostatic repulsion between electrons, also play a crucial role in determining the overall stability of an anion. In summary, a negative electron affinity for an element suggests that its anion would generally be more stable than its neutral atom. However, the stability of an anion is determined by variables like the energy required to overcome electron repulsion and the overall electron configuration.