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 \(\mathrm{Cl}^{-}\) ion. c. the \(\mathrm{Cl}^{+}\) ion. d. the \(F\) atom. e. none of these.

Short answer

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

Step-by-step solution

Option a: The Cl atom

Since chlorine has a high electron affinity, adding an electron to a Cl atom will release a significant amount of energy. However, removing an electron from the Cl atom would require even more energy, as it has a high ionization energy. So, ionization energy for the chlorine atom is not equal to the electron affinity for the Cl atom.

Option b: The \(\mathrm{Cl}^{-}\) ion

The chlorine atom gains an electron to become the \(\mathrm{Cl}^-\) ion, which corresponds to its electron affinity. On the other hand, the ionization energy of the \(\mathrm{Cl}^-\) ion corresponds to the requirement of removing an electron from the \(\mathrm{Cl}^-\) ion, returning it to its neutral state (Cl atom). In this case, the ionization energy of \(\mathrm{Cl}^-\) is equal to the electron affinity of the Cl atom.

Option c: The \(\mathrm{Cl}^{+}\) ion

Removing an electron from the Cl atom will result in the formation of \(\mathrm{Cl}^+\) ion, which refers to its ionization energy. However, the electron affinity of \(\mathrm{Cl}^+\) is not equal to the ionization energy of the Cl atom since adding an electron to a \(\mathrm{Cl}^+\) ion yields a Cl atom, which has a higher electron affinity than the ionization energy for the \(\mathrm{Cl}^+\) ion.

Option d: The \(F\) atom

Fluorine has a higher electron affinity compared to chlorine and an even higher ionization energy than chlorine. Therefore, ionization energy of chlorine is not equal to the electron affinity of the \(F\) atom.

Option e: None of these

Only one answer should be correct, so option e could not be that answer since an earlier option is the correct response. Based on the analysis, the correct answer is: b. The \(\mathrm{Cl}^-\) ion.

Key concepts

Ionization Energy

Ionization energy is the energy required to remove an electron from a neutral atom in its gaseous state. This energy quantifies the strength with which an atom holds onto its electrons.

The higher the ionization energy, the more challenging it is to remove an electron. For example, chlorine has a relatively high ionization energy in comparison to other elements because it is eager to maintain its electrons to complete its valence shell.

Factors affecting ionization energy include:

• Atomic radius: Larger atoms have lower ionization energies because their outer electrons are further from the nucleus.
• Nuclear charge: Greater nuclear charge increases ionization energy, as the electrons are pulled more strongly towards the nucleus.
• Electron shielding: More electron shells mean more shielding, usually resulting in lower ionization energy.

Understanding ionization energy helps explain why the chlorine atom retains its electron configuration so vehemently.

Electron Affinity

Electron affinity refers to the amount of energy released when an electron is added to a neutral atom to form a negative ion. This property indicates how strongly an atom can attract additional electrons. Chlorine, for instance, shows a high electron affinity as it readily accepts an electron to form a stable chloride ion (\(\mathrm{Cl}^-\)).

Some important points about electron affinity:

• It is usually expressed in terms of the energy change involved.
• High electron affinity values signify that energy is released when an atom gains an electron, implying that the atom becomes more stable.
• Trends usually show electron affinity decreasing down a group and increasing across a period on the periodic table.

When exploring elements like chlorine, recognizing its substantial electron affinity helps us understand its behavior as a strong oxidizing agent.

Chlorine Atom

A chlorine atom has 17 protons and typically 17 electrons. In its stable form, the configuration seeks to have a full outer electron shell.

This results in its high tendency to gain an electron for achieving a noble gas configuration.

Characteristics of the chlorine atom include:

• Belonging to the halogen group (Group 17) on the periodic table.
• High reactivity due to its electron configuration of an unfilled valence shell.
• A typical chlorine atom has significant electronegativity, allowing it to attract electrons easily.

These properties lead to its extensive use in various chemical reactions, such as in forming compounds like sodium chloride.

Chemical Ion

Chemical ions are charged particles that form when atoms lose or gain electrons. They are crucial in many chemical reactions and processes.

For example, the chloride ion (\(\mathrm{Cl}^-\)) originates from a chlorine atom gaining an electron, demonstrating the atom's affinity to achieve stable electronic arrangement.

Key features of chemical ions are:

• Cations are positive ions formed by losing electrons, like sodium (\(\mathrm{Na}^+\)).
• Anions are negative ions, such as chloride (\(\mathrm{Cl}^-\)), formed by gaining electrons.
• Ions participate in forming ionic compounds through electrostatic attractions between opposite charges.

This transformation into ions is vital for understanding interactions in compounds and essential processes like electrical conductivity in solutions.