Which alkali metal, based on ionization energies, would you expect to undergo the most exothermic reaction with chlorine gas?

Verified step by step guidance

1. Identify the alkali metals in the periodic table. These include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).
2. Understand that ionization energy is the energy required to remove an electron from an atom. Alkali metals have low ionization energies, which decrease as you move down the group.
3. Recognize that a lower ionization energy means the metal can more easily lose an electron to form a cation, which is a key step in reacting with chlorine gas to form a salt.
4. Consider that the most exothermic reaction will occur with the alkali metal that can most easily lose its electron, which corresponds to the metal with the lowest ionization energy.
5. Determine which alkali metal has the lowest ionization energy by looking at periodic trends, noting that ionization energy decreases down the group, making cesium (Cs) the most likely candidate for the most exothermic reaction with chlorine gas.