Which of the following has highest bond energy?

  1. #S-S#
  2. #O-O#
  3. #Se-Se#
  4. #Te-Te#

1 Answer
anor277
Nov 25, 2017

I would assume #"option 2."#

Explanation:

Why? We ASSUME that we interrogate the strength of an #"element-element single bond,"# i.e. #"peroxides, persulfides, etc."#

From first principles we would expect that the smaller the atom, the BETTER the overlap between electrons, and the SHORTER the #"element-element"# bond.

But we must interrogate data as physical scientists...

chegg.com

The data are quoted in #"pm"-=10^-12*m#. (Most inorganic chemists would prefer to use units of #"Angstroms"-=1xx10^-10*m#.)

Do the measured bond energies, and the bond distances, support my argument? Bugger me, they do not. The homonuclear tellurium and selenium bonds are not reported. However the peroxo bond is #1.48xx10^-10*m# long, and has a bond enthalpy of #204*kJ*mol^-1#, and the persulfide bond is #2.04xx10^-10*m# long, and has a bond enthalpy of #266*kJ*mol^-1#.

We assume that the lone-pair/lone-pair repulsion that occurs for the peroxide link, and these lone-pairs are small, and should interact destructively, weakens and lengthens the #O-O# bond.

I hope the quoted data are right. But on this basis the question is quite unfair, and certainly you should request feedback from your lecturer/tutor on this question.

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