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What natural elements float with buoyancy?
Answer 1:

I am first going to guess that when you say floating, you mean in water. There are very few elements that float in water. To float in water, their density would have to be less than the density of water. Something that has higher density has more stuff packed into a small space. Something with lower density has less stuff packed into that same space. For example, a chunk of metal the size of a brick will have much higher density than a chunk of Styrofoam the same size.

So to see if something can float in water, you can compare the density of it to the density of water. I found a great periodic table click here that has the density of each element in the top right corner.

Going in order, we can see that hydrogen and helium both have densities less than water, which would be 1.0 g/mL. Those are gases, and so you can imagine a gas bubble floating to the surface and escaping, just like carbon dioxide does in bubbly soda. The next one that we see is lithium. Lithium is definitely a lower density than water. So is sodium (element symbol Na) below it and potassium (element symbol K)! Unfortunately, all three of those elements are really reactive with water, to the point that if you drop a small amount in, it can be like a small explosion!

Some other elements that would float in water would include nitrogen, oxygen, fluorine, neon, chlorine, and argon. (On the chart, it says that argon has a density of 1.784, but this is in g/L. Water has a density of 1.0 g/mL which is equal to 1000 g/L. So argon is definitely less dense than water!)

All of those elements are gases. So they would float, but you would have to put them into the water as bubbles. If you meant to ask what elements would float in air, the density of air is about 1.2 g/L. You might have seen a helium balloon take off into the air when you let it go, so you know that helium can float in air. Hydrogen can, too. And according to that chart, it looks like neon would also float in air. Hope that helps!

Answer 2:

It depends more on the state of the element. Carbon dioxide for example is a gas (it's also a compound), but its frozen form, dry ice, sinks.

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