Here's why:
* Electrochemical Series: Lithium sits at the very top of the electrochemical series, which ranks elements based on their tendency to lose electrons (oxidize). The higher the element is on the series, the more easily it oxidizes.
* Low Ionization Energy: Lithium has a very low ionization energy, meaning it takes very little energy to remove an electron from its atom. This makes it very susceptible to oxidation.
* High Reactivity: Lithium is extremely reactive with air and water, readily forming lithium oxide (Li₂O) and lithium hydroxide (LiOH) respectively.
Important Note: While lithium is the most readily oxidized metal, it's crucial to remember that other metals can also be oxidized under specific conditions.