An experiment suggested by a PhD student may rewrite chemistry textbooks

Re:An experiment suggested by a PhD student may rewrite chem... by nl on Thursday June 25, 2020 @01:35AM (#23637255)

> It's true that it's less dense, but "float" is a huge understatement. That is, it skitters, like water on a hot frying pan.

No, if you wrapped it in some impermeable coating so it couldn't react with water it would still float.

> But, I guess because it's less dense, it doesn't detonate as often as sodium or potassium do.

It doesn't "detonate as often" because it is less reactive than sodium and potassium because it is less likely to lose it's outer electron because that outer electron is closer to the nucleus.

That also means it is denser.

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Re:An experiment suggested by a PhD student may rewrite chem... by jtbayly on Thursday June 25, 2020 @05:25AM (#23638622)

Lithium is denser then sodium?

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Re:An experiment suggested by a PhD student may rewrite chem... by mirimir on Thursday June 25, 2020 @04:16AM (#23638133)

OK, sure. But TFA doesn't mention any coating.

I found a resource that corroborates what I said about behavior on water.[0] But it doesn't get into why that is.

And about density and electronegativity:

        g/cm^3   χ (Pauling)  1st ionization energy (kJ/mol)
   Li   0.535    0.98         520
   Na   0.968    0.93         496
   K    0.856    0.84         419

The difference in density is larger than that for electronegativity and 1st ionization energy. But yes, all three arguably play a role. Still, for Li vs Na, density seems like the major factor.

0) https://www.reference.com/science/alkali-metals-react-water-...

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