Though I got to directly interact with Hg as a kid, I don’t remember playing with Li. Na was in oil in the Chem Lab.
Lithium & Sodium are very similar, alkali metals, VERY reactive. The sodium is held under oil otherwise it would oxidize rapidly in air and turn grey > black or catch fire and burn in water, as would lithium. Very reactive in contact with organic matter, burst into flame style.
Hg mercury, the metal, is actually not very reactive except to VERY strong acids and oddly, aluminum. It dissolves the oxide layer that always forms on aluminum in air and so it has the apparent effect of corroding the daylights out of aluminum, almost as if it was a strong acid attacking the aluminum.