What is actual difference between atomic hydrogen and nascent hydrogen?
Nascent hydrogen is an old term, outdated even, postulated to describe a "species" of atomic hydrogen gas that was produced in situ (on site), to claim that it is a "highly reactive" version of
(Really, it is just an overly-simplified explanation of why such "species" [which are not new to us] tend to be more reactive than bottled ones stored over time.)
#"Zn"(s) + "H"_2"SO"_4(aq) -> "ZnSO"_4(aq) + overbrace(2"H"(g))^"'Nascent Hydrogen'"#
This tends to be in the context of dissolving-metal reactions. Although I usually see this reaction forming
(These days, we know that of course it's more reactive than
Atomic hydrogen is more generalized, and is simply the
#"H"_2(g) + "436 kJ" -> 2"H"(g)#
This is just in general, and out of context of dissolving-metal reactions. I don't think we use the term "nascent hydrogen" anymore...