Write equations that show the processes that describe the first, second, and third ionization energies of a chlorine atom. Which process would require the least amount of energy?

Verified step by step guidance

1. Step 1: The first ionization energy refers to the energy required to remove the first electron from an atom. For a chlorine atom, this process can be represented as follows: Cl(g) -> Cl+(g) + e-. This equation shows that a gaseous chlorine atom loses one electron to form a gaseous chlorine ion.
2. Step 2: The second ionization energy refers to the energy required to remove a second electron from an atom. For a chlorine atom that has already lost one electron, this process can be represented as follows: Cl+(g) -> Cl2+(g) + e-. This equation shows that a gaseous chlorine ion loses another electron to form a doubly charged gaseous chlorine ion.
3. Step 3: The third ionization energy refers to the energy required to remove a third electron from an atom. For a chlorine atom that has already lost two electrons, this process can be represented as follows: Cl2+(g) -> Cl3+(g) + e-. This equation shows that a doubly charged gaseous chlorine ion loses another electron to form a triply charged gaseous chlorine ion.
4. Step 4: In general, the first ionization energy is the smallest because the electron is being removed from a neutral atom. As more electrons are removed, the ion becomes more positively charged, which makes it harder to remove additional electrons. Therefore, the first ionization process would require the least amount of energy.

Key Concepts

Ionization Energy

Ionization energy is the energy required to remove an electron from a gaseous atom or ion. It is a measure of how strongly an atom holds onto its electrons. The first ionization energy refers to the removal of the first electron, while subsequent ionization energies involve removing additional electrons from the resulting cations. Generally, ionization energy increases with each successive electron removed due to the increasing positive charge of the ion.

Chlorine Atom and Its Electron Configuration

Chlorine (Cl) has an atomic number of 17, meaning it has 17 electrons arranged in its electron configuration as [Ne] 3s² 3p⁵. The outermost electrons, particularly those in the 3s and 3p orbitals, are involved in ionization processes. Understanding the electron configuration is crucial for predicting how many electrons can be removed and the energy changes associated with these removals.

Trends in Ionization Energies

Ionization energies exhibit periodic trends; they generally increase across a period and decrease down a group in the periodic table. For chlorine, the first ionization energy is lower than the second and third because removing an electron from a neutral atom is easier than removing one from a positively charged ion. Therefore, the first ionization energy will require the least amount of energy compared to the second and third ionization energies.