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""There are no periodic trends""
This section/sentence is a bit wrong headed. 
Periodic trends are those which repeat from period to period (e.g. noble gas behavior recurring). What this really means to talk about is ""horizontal trends"" across the period. What the article means to say, I guess, is that horizontal trends are due to a quantum shell filling, and since 1s fills within 2 electrons, there's not much scope to look at 'trends'. It's also perhaps worth noting that when Mendelev put the ""periodic"" table together, he didn't know the noble gases existed, so all he had to place from what would become period 1 was hydrogen.  "