Explosive Metals

So, now you know that elements like sodium and potassium are metals. But, you might be thinking, isn't table salt also known as sodium chloride? Is salt a metal? And don't bananas and oranges contain a lot of the nutrient potassium? Do these fruits contain pieces of metal?

Well, no. Chemical elements come in different forms, depending on whether they're pure substances or in compounds, with two or more elements combined. Pure sodium and pure potassium are metals. They're gray and shiny, like most metals. They can be cut with a kitchen knife, which is kind of weird. But they are definitely metals. However, when sodium combines with chlorine (another element), it makes sodium chloride, a compound with properties very different from those of the original elements.

One more thing about the alkali metals, which include sodium and potassium, but also lithium, rubidium, cesium, and francium - they explode and burn when they contact water! This is much too dangerous for you to try on your own, but here's a link to a video in which you can see the Mythbusters playing with sodium and potassium.