What is the difference between "atomic hydrogen" and "nascent hydrogen"?
Is your book by chance very old? From the Wikipedia entry for "nascent hydrogen":  


  Nascent hydrogen is purported to consist of a chemically reactive form
  of hydrogen that is freshly generated, hence nascent. Molecular
  hydrogen ($\ce{H2}$), which is the normal form of this element, is unreactive
  toward organic compounds, so a special state of hydrogen was once
  invoked to explain certain kinds of hydrogenations. Mechanistic
  understanding of such reactions is now available, and the concept of
  nascent hydrogen is discounted, even ridiculed.  


Then, by example of how this concept came to be:  


  Reductions of esters to give alcohols using a mixture of sodium and
  alcohols is called the Bouveault–Blanc reduction. It is an old
  reaction that has largely been superseded by alternative methods. At
  the time of popularity, the process caused much puzzlement because
  esters are unreactive toward hydrogen. It was also known that sodium
  reacts with alcohols to release $\ce{H2}$. it was concluded that some freshly
  generated ("nascent") hydrogen was responsible for this remarkable
  reaction. Subsequent studies have shown that this reaction proceeds
  via electron-transfer from metallic sodium to the ester substrate
  followed by protonation of the reduced intermediate. The evolution
  of hydrogen by the reaction of sodium and alcohol is purely a
  competitive reaction, the sole benefit being that in the presence of
  sufficient alkoxide, the sodium/alcohol reaction slows.


So in general, at least toward organic compounds, your relative reactivities of hydrogen species are correct if you take out "nascent" hydrogen so that:  

$$\ce{H2} \lt \rm atomic~hydrogen$$