This question has alreadey been asked at least twice in last fortnight. Pl have a habit to check previous threads.
And another easy way was google which anyway people don't want to do.
The differences are in chemical properties, mechanical properties, applicattions in the first three about the last one (etc) i am not sure what it means because it may mean from H to Hs with all their compounds and mixtures and solid solutions.
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Fantastic ideas for a Fantastic World, I make the illogical logical.They put me in cars,they put me in yer tv.They put me in stereos and those little radios you stick in your ears.They even put me in watches, they have teeny gremlins for your watches