Why do lithium, sodium and potassium float on water?

1 Answer

Answer:

They all have densities that are less than water's.

Explanation:

Lithium, sodium, and potassium are all very light elements, and metals that are made purely of them will have low densities.

In fact, lithium has the lowest density of all solid elements, #"0.534 g/cm"^3# compared to water with #"1.000 g/cm"^3#. They also all react violently with water, so even though they float, they won't stay there for very long.