Why couldn't mendeleev have predicted the noble gases?

Question

What are some possible reasons as to why Mendeleev couldn't predict the existence of the noble gases?

Answer 1

1. It is really true that noble gases are inert- meaning not getting into reaction with almost anything- so he just couldnt have met them in any reaction
2. the main reason what youre looking for is regarding the periodic table. He was the one who has seen the periodical features of certain elements and concluded that it has to do with molecular mass, so he just put them into order, and found out that there are cycles, each of seven (in case of nonmetals and alcali metals) so he drew the periodic table more or less as you see it today. Obviously back then there were a couple of elements that hasnt been discovered yet, but according to changing properties they had a place in the p. table. This is how he predicted certain elements. ex: Li, Na, Ka, Rb all behaved the same, (alcalimetals) so they end up in a column of their own. but the noble gases werent known about at all, and they are situated in the 18th column, not knowing the exact electronic structure he had no way of predicting there would be a new column there. Main idea would be that the periodic table worked on similar properties, both chemical and physical, and NOT on electronic structure of an atom, so you could place only the things that had at least one or two representatives already.

Answer 2

In those days, all chemicals were detected by chemical analysis - breaking down compounds until they could be broken down no more. There is no chemical way of detecting the inert gases.