And yeah, TFA is a little lame. I laughed at "lithium...floats on water". 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. But, I guess because it's less dense, it doesn't detonate as often as sodium or potassium do.
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.
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
0) https://www.reference.com/science/alkali-metals-react-water-...
Putting a small lump in a bucket outdoors using a rope-activated rig sounds pretty reasonable, though.