Chapter 7, Problem 56A

Interpretation Introduction

Interpretation:

Whether Neon or Fluorine has higher potential energy needs to be determined.

Concept introduction:

The ionization energy is the energy required to removed the outermost electrons, namely the valence electrons. During this process, energy is absorbed and through this method, a cation is formed. As one go across a period, ionization energy increases and on going down a group, ionization energy decreases.

Answer to Problem 56A

Fluorine has tendency to gain one electron and is more reactive. Hence, it has high potential energy.

Explanation of Solution

Neon belongs to Nobel gas or group 18. The electronic configuration is ${\text{1s}}^{\text{2}}2{\text{s}}^{2}2{\text{p}}^{\text{6}}$. It has an octet structure. As it is stable, it has less ionization energy.

Fluorine belongs to halogen group or group 7. It has electronic configuration as ${\text{ns}}^{\text{2}}{\text{np}}^{\text{5}}$. It has 7 valence electrons.

Figure 1

It is known that when we move across the table moving from left to right, elements of the same period have same number of shells. The only difference is that the atomic number increases indicating number of protons increases or the number of electrons increases.

Therefore, when we move from left to right, as the number of electrons increases, the force of attraction between the outermost electrons and the nucleus is increased.

Figure 2

Fluorine has vacancy to accommodate one electron and will absorb one electron easily. This results in higher potential energy as it is more reactive.

Conclusion

Fluorine has tendency to gain one electron and is more reactive. Hence, it has high potential energy.