Due to the instability of some elements, they are prone to react with each other and volatilize easily. For safety reasons, they are specially treated, replaced by compounds containing such elements, or replaced by substances of similar shape and color. And some rare chemical elements that are not easy to collect are especially replaced.
Q: A customer reflects that Potassium and Mercury should both are silvery looking metals.
A: In the actual production, we give these two elements special treatment for safety.
Potassium is harmful, so we used something similar in color and shape to replace it, so you can see it is silvery white in this elements table.
Mercury is also harmful liquid substance, so Mercuric compound was used instead.