Does the toxicity of an element depend on the state of matter (liquid, solid, gas)?
Could there be an element, which is totally non-toxic when it is solid, but toxic when it is liquid. Which elements would fall in that category?
$\begingroup$
$\endgroup$
State of matter has the major effect how much and which way the substance gets into the body. That means, while toxicity is the same, the effective toxicity differs very much.
Similarly, if a medicine is applied, the total amount of the drug is just a part of the effect. The other part is the form and the way how it is applied.
Generally, toxicity ( or medication effect ) decreases in order:
gas/vapour > inhaled aerosol or infusion liquid > swallowed liquid/solution > solid/dust > solid/pieces
as it follows the effectiveness of the substance transfer to body fluids on molecular level.
Typical example is mercury.
Liquid mercury has relatively low toxicity. If you digest it, the major symptom is diarrhea.
Mercury vapours, that are created by slow evaporation of spilled mercury, are highly toxic, if they are inhaled.
Another case are insoluble salts of poisonous metals. Solutions of barium salts are poisonous, but ingestion of thick milk ( rather fluid mash ) of insoluble barium sulphate is/was used in roentgen examination of digestion tract.
