Thank you!DrClaude said:The noble were not included in Mendeleev's table, as they had not been discovered (or isolated) at the time. It is only in 1894 after Ramsey discovered argon that it was added to the periodic table. I guess it was added at the right place because of its mass, which you get by simply weighing the gas.
I don't think this does justice to Mendeleev. There was hardly a chemist a his time with his knowledge and he used essentially all of the information of available at his time to set up his periodic system. This included also physical characteristics like melting and boiling points and he even re-arranged the position of some elements like Beryllium because it's other properties didn't fit to that deduced from it assumed valence, which was also not known with certainty at that time.Anithadhruvbud said:These noble gases do not react with hydrogen or oxygen.but Mendeleev basically classified by observing their reactions with hydrogen or oxygen.
But still mendeleev did something extraordinary.It was only after observing his table that Moseley was able to come up with his own.DrMendeleev 5387549 said:I don't think this does justice to Mendeleev. There was hardly a chemist a his time with his knowledge and he used essentially all of the information of available at his time to set up his periodic system. This included also physical characteristics like melting and boiling points and he even re-arranged the position of some elements like Beryllium because it's other properties didn't fit to that deduced from it assumed valence, which was also not known with certainty at that time.