https://en.m.wikipedia.org/wiki/Metal_toxicity
It appears as there if is little correlation between metal density and toxicity
> Toxic metals sometimes imitate the action of an essential element in the body, interfering with the metabolic process resulting in illness. Many metals, particularly heavy metals are toxic
Metal toxicity is the correlation between density and reactivity.
Iron and manganese are limited exceptions where iron is about 84% of hemoglobin, which is about 80% of red blood cells, but its toxic (though in larger doses) matches almost exactly the implications of other metal toxicity.
No, it doesn't. Your quote truncates a sentence that supports GP's point.
First sentence of third paragraph in linked wiki page.
> Although the gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts (gold compounds) by any known chemical process which would be encountered in the human body.
This is true of known natural metabolic processes, but not true with connection to certain drug interactions. Gold is not chemically inert and can be converted into an ion or gold salt, even within the body, when mixed with other reactive non-toxic chemicals. Gold metal is popularly consumed in trace amounts of certain alcoholic beverages and there are many medications that should not be taken in connection with alcohol for many different metabolic altering processes. I am not sure if it has been thoroughly tested, but a combination of gold and nangarin could also result in potentially toxic consequences, which is why certain fruits are forbidden with consumption of certain other chemicals/drugs.
This is exceedingly rare though, since platinum group metals are so expensive, but the same conditions are observed with other platinum group metals. Silver is more toxic than gold because it is more reactive, but the behaviors are similar. A major symptom of advanced toxicity from platinum group metals is a changing of skin color towards the metallic color of the metal toxin.
Gold has a far lower ionization energy than you are giving it credit for, which means it is capable of becoming toxic with relatively minor interactions. The safe for consumption statement implies interactions natural to human physiology are not likely to make gold toxic, but that doesn't account for other things humans consume that do trigger reactions not normal to human physiology.
Like gold we generally believe fruit juice is safe for consumption. Fruit juice is even classified as safe for consumption, like gold, by the FDA. This was proven to be not completely true when the price of grapefruit production fell in the 1980s. Certain chemical interactions with fruit juice will make you sick and in extreme cases will kill you. This phenomenon was only discovered because of numerous associated deaths.
* https://en.wikipedia.org/wiki/Grapefruit%E2%80%93drug_intera...