With an atomic number of three, lithium is the third lightest element on the periodic table and the lightest solid at room temperature and pressure.

For almost two centuries after its discovery, lithium didn't have much in the way of practical uses. However, in the last few decades, its status changed,

and it went from being one of the least useful elements to one of the most important elements to the world's economy.

Lithium is also the source of one of the biggest unexplained problems in physics.

Learn more about lithium, one of the oddest elements on the periodic table

on this episode of Everything Everywhere Daily. To start talking about lithium, I might as well get some basic facts about the element

out of the way. As I mentioned in the introduction

lithium is the third lightest element on the periodic table it's right behind

hydrogen and helium with an atomic number of three unlike hydrogen hydrogen and helium, however, it is a solid under normal

conditions. It sits at the top of the first group in the periodic table, the alkali

metals. In addition to lithium, this includes other elements such as sodium and potassium.

What defines all these elements, including lithium, is that they only have a single electron

in their outermost shell.

Like every alkali metal, this makes lithium highly reactive,

although it is the least reactive of the alkali metals.

As with other alkali metals, you have to store them in something like mineral oil so it doesn't

react with the oxygen in the atmosphere. Lithium is never found in its elemental

form as a pure metal because it's so reactive and it easily bonds with other elements.

When it is purified into its metallic form

and cut to expose a fresh surface, it can be shiny like other metals, but its high

reactivity causes it to corrode very fast and turn into a dull silvery gray.

And I should note that yeah you actually can cut lithium with a knife because it's just that

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