Question

When going through list of oxidation states on Wikipedia I encounterd there that sodium, potassium, rubidium and caesium exhibit oxidation states of -1, but not lithium, even though its electronegativity is more than that of the others. How's that possible? Can some one provide an example.

Answer 1

The alkali metals sodium, potassium, rubidium, and caesium can exhibit an oxidation state of -1. However, lithium does not exhibit an oxidation state of -1. This is because the electron configuration of lithium is different from the other alkali metals, allowing it to form compounds with an oxidation state of +1.

Step-by-step explanation:

The oxidation states of alkali metals such as sodium, potassium, rubidium, and caesium are generally +1. However, they can also exhibit oxidation states of -1 in certain compounds. On the other hand, the selected alkali metal lithium does not exhibit an oxidation state of -1 despite having a higher electronegativity than the others in the group.

This is because the electron configuration of lithium (Li) follows the pattern of the alkali metals sodium (Na) and potassium (K), where the next electron is added to the 4s level rather than the 3d level. Hence, lithium has an electron configuration of [He]2s¹, which allows it to form compounds with an oxidation state of +1.