Question

The correct order of electron gain enthalpies of Cl, F, Te and Po is

• A. F < Cl < Te < Po
• B. Po < Te < F < Cl
• C. Te < Po < Cl < F
• D. Cl < F < Te < Po

Answer 1

The Correct Option is A

To determine the correct order of electron gain enthalpies for Cl, F, Te, and Po, we need to understand the concept of electron gain enthalpy, which is the energy change when an electron is added to a neutral atom in the gaseous state to form a negative ion. The more negative the electron gain enthalpy, the greater the tendency of the atom to accept an electron.

Atoms with higher electronegativity and smaller atomic radii typically have more negative electron gain enthalpy values. However, due to the small size of fluorine, there is significant electron-electron repulsion when an extra electron is added, making its electron gain enthalpy less negative than expected.

1. Chlorine (Cl): Chlorine has a more negative electron gain enthalpy compared to fluorine due to less repulsion among electrons when gaining an electron.
2. Fluorine (F): Despite its high electronegativity, the small size of fluorine atoms leads to increased electron-electron repulsions, making its electron gain enthalpy less negative than that of chlorine.
3. Tellurium (Te) and Polonium (Po): These elements belong to the oxygen family (Group 16) and their electron gain enthalpies are less negative than those of halogens (like Cl and F) because of their larger atomic size and decreased electronegativity.

From the analysis, chlorine has the most negative electron gain enthalpy, followed by fluorine, and then tellurium and polonium. Therefore, the correct order is F < Cl < Te < Po.

In conclusion, the correct order of electron gain enthalpies is: F < Cl < Te < Po.