Question

Choose the best response for the following: The ionization energy for the chlorine atom is equal in magnitude to the electron affinity for a. the Cl atom. b. the Cl \(^{-}\) ion. c. the Cl \(^{+}\) ion. d. the F atom. e. none of these. Explain each choice. Justify your choice, and for the choices you did not select, explain what is incorrect about them.

Short answer

The correct answer is b: the ionization energy for the chlorine atom is equal in magnitude to the electron affinity for the Cl\(^{-}\) ion. This is because when an electron is added to the Cl atom, it forms a Cl\(^{-}\) ion and releases energy, which is equivalent to the energy required to remove the same electron from the Cl\(^{-}\) ion to form the neutral Cl atom.

Step-by-step solution

Analyze Option a

Option a suggests that the ionization energy of the chlorine atom is equal to the electron affinity of the Cl atom. However, this is not the case. Ionization energy is the energy required to remove an electron while electron affinity is the energy change when an electron is added. These two processes are not equal in the case of the same atom.

Analyze Option b

Option b suggests that the ionization energy of the chlorine atom is equal to the electron affinity of the Cl\(^{-}\) ion. This option is correct. When electron is added to the Cl atom, it forms a Cl\(^{-}\) ion and releases energy, which is equivalent to the energy required to remove the same electron from the Cl\(^{-}\) ion to form the neutral Cl atom. The ionization energy for chlorine is thus equal in magnitude to the electron affinity for the Cl\(^{-}\) ion.

Analyze Option c

Option c suggests that the ionization energy of the chlorine atom is equal to the electron affinity of the Cl\(^{+}\) ion. This is incorrect because ionization energy is related to the removal of an electron and electron affinity is related to the addition of an electron. The electron affinity of the Cl\(^{+}\) ion, however, is related to the energy change when an electron is added to the Cl\(^{+}\) ion, not when it is removed.

Analyze Option d

Option d suggests that the ionization energy of the chlorine atom is equal to the electron affinity of the F atom. This is incorrect because ionization energy and electron affinity are properties that depend on the specific element and its electronic configuration. The ionization energy of chlorine and the electron affinity of fluorine are not related in terms of magnitude.

Analyze Option e

Option e suggests that none of the given choices are correct. Since we have already determined that option b is the correct choice, option e is incorrect.

Conclusion

The correct answer is b: the ionization energy for the chlorine atom is equal in magnitude to the electron affinity for the Cl\(^{-}\) ion.

Key concepts

Electron Affinity

Electron affinity is a fascinating concept in chemistry. It represents the energy change that occurs when an electron is added to a neutral atom in the gaseous state. The more energy released, the higher the electron affinity.
Understanding electron affinity is crucial because it provides insights into an element's ability to gain electrons. In a way, it measures how much an atom wants an electron.

• High electron affinity indicates a strong attraction for electrons.
• Low electron affinity suggests a weaker tendency to attract electrons.

Typically, nonmetals have higher electron affinities than metals. This is because nonmetals tend to gain electrons to achieve a stable electron configuration, while metals tend to lose electrons.

Chlorine Atom

The chlorine atom is an essential element in the periodic table, known for its high reactivity and significant role in various chemical reactions.
As a halogen, chlorine belongs to Group 17 in the periodic table and has the electron configuration exttt{[Ne] 3s² 3p⁵}. This configuration indicates that chlorine has seven electrons in its outer shell, needing only one more to reach the stable configuration of a noble gas.
Chlorine's high electron affinity makes it effective at gaining an electron to form the chloride ion (Cl⁻). This tendency to form anions is why chlorine is often found participating in ionic bonds, such as in sodium chloride (table salt).

• Highly reactive nonmetal.
• Seven valence electrons, needs one to complete its outer shell.
• Participates widely in ionic compounds.

Ions

Ions are charged particles that form when atoms gain or lose electrons. They can be either positively charged (cations) or negatively charged (anions).

• Cations occur when an atom loses electrons, such as sodium ( exttt{Na⁺}).
• Anions occur when an atom gains electrons, such as chloride ( exttt{Cl⁻}).

The formation of ions is key to many chemical processes, especially in the formation of ionic compounds, which are held together by the electrostatic forces between oppositely charged ions. These interactions contribute to the characteristic high melting and boiling points of ionic compounds.
In the context of electron affinity, the focus is often on the formation of anions, where energy is released when electrons are added to neutral atoms to form negatively charged ions.

Energy Change

Energy change is a core concept in understanding processes like ionization and electron affinity. It involves the transformation of energy during the addition or removal of electrons from an atom.
When examining chemical reactions and formations, both energy absorption and release can occur. In terms of electron affinity, we specifically look at the release of energy when an electron is added.
For example:

• During ionization, energy is required to remove an electron from an atom. This is called ionization energy.
• During the process of gaining an electron (electron affinity), energy is released.

These energy changes are important because they help predict the behavior of elements in chemical reactions and their tendency to form ions. Understanding these concepts aids in grasping how different elements interact and bond with one another.