Which element would most likely have an electron affinity measuring closest to zero?
A. Na
B. Ar
C. Rb
D. Ar
Answer (1)
Electron affinity measures an atom's tendency to gain an electron.
Argon (Ar) has a stable electron configuration.
Stable electron configurations result in electron affinities close to zero.
Therefore, Argon (Ar) is most likely to have an electron affinity closest to zero. A r
Explanation
Understanding Electron Affinity Electron affinity is the energy change when an electron is added to a neutral atom in the gaseous phase. Elements with stable electron configurations are less likely to accept an electron, resulting in electron affinities close to zero.
Analyzing Electron Configurations Let's consider the electron configurations of the given elements:
Na (Sodium): [Ne] 3s¹ (Alkali metal, tends to lose an electron)
Ag (Silver): [Kr] 4d¹⁰ 5s¹ (Transition metal)
Rb (Rubidium): [Kr] 5s¹ (Alkali metal, tends to lose an electron)
Ar (Argon): [Ne] 3s² 3p⁶ (Noble gas, stable electron configuration)
Identifying the Element with Electron Affinity Close to Zero Argon (Ar) has a complete octet in its outermost shell (3s² 3p⁶), making it very stable. Therefore, it has little to no tendency to gain an electron.
Comparing with Other Elements The other elements (Na, Ag, and Rb) are more likely to lose electrons to achieve a stable electron configuration, so they will have more negative electron affinities.
Examples
Understanding electron affinity helps predict how elements will react with each other to form chemical bonds. For example, elements with high electron affinities (like chlorine) tend to readily accept electrons from elements with low ionization energies (like sodium), forming ionic compounds such as sodium chloride (table salt). This concept is crucial in designing new materials and understanding chemical reactions.
