[anoxor]

The orbitals of the lowest elements on the periodic table are the largest in diameter and most flexible in bonding and rebonding.

Their ability to easily make relatively short lived bonds is the key.

These metals are often super poisonous for the same reason (heavy metal poisoning). They enter a biological system and effectively randomize a whole lot of bonds and molecules you want to be stable over decades.

[canadaduane]

By "lowest elements" do you mean elements with lowest atomic number (Hydrogen, Helium, Lithium, etc.), or closest to the bottom of a chart hanging on a wall (Rubinium, Strontium, Yttrium, etc.)?

[selimthegrim]

It would seem to be the latter, given the reference to heavy metals (they probably mean noble metals more likely)

[ncmncm]

No. They are contrasting the elements operated on, mostly light elements, with heavier ones used in catalysts that are also toxic, for reasons.

[kurupt213]

Not really. It’s because of the D- orbital configuration of the coinage metal family.