Been learning in biology about $\ce{O2}$'s role as an oxidizing agent, but I don't really understand how $\ce{O2}$ can take electrons from anything if it's not reactive....

  • $\begingroup$ Also, see this: chemistry.stackexchange.com/questions/90773/… $\endgroup$ Commented Apr 12, 2018 at 16:14
  • $\begingroup$ And before I forget, welcome to Chemistry.SE! Take the tour to familiarize yourself with the site! We hope you enjoy your stay! $\endgroup$ Commented Apr 12, 2018 at 16:15
  • $\begingroup$ O2 is pretty reactive, even though each atom's valence shell is full. $\endgroup$ Commented Apr 12, 2018 at 16:23
  • $\begingroup$ @Mithoron But that question doesn't have an answer that metaphorically explains everything as domestic abuse. $\endgroup$
    – Stian
    Commented Apr 13, 2018 at 13:14

1 Answer 1


Most compounds consist of atoms that have "filled" their valence shells. It is basically what defines "reasonably" stable molecules. That does not mean that they cannot react with other molecules. Nature always seeks to find the lowest energies possible for its molecules, and the oxygen molecule has a very high potential energy.

The oxygen molecule is like two bullies who live together. They'd rather find a pair of victims that are weaker than themselves, split up and live an abusive but for them good life alongside their weaker partners. There are worse compounds out there, like the homicidal maniac Chlorine Trifluoride who will rip apart the stablest of marriages to abominable and atrocious results.

  • $\begingroup$ Lolz, nice vivid answer. I take it that's because oxygen is so electronegative. Thanks. Edit: but wouldn't it take something more electronegative than oxygen (ie fluorine) to break the bond of an oxygen to another oxygen? $\endgroup$ Commented Apr 12, 2018 at 18:52
  • $\begingroup$ @JurpBurper Victims and bullies. Or bullies and homicidal maniacs. As long as there is difference between them and the resulting molecule(s) are stable reaction can happen. If a molecule that is highly electronegative find a molecule that is much less so, and the ambient temperature is high enough for it to happen, the reaction will happen and the result is one or more averagely electronegative ones. It is like hot and cold, nature prefers lukewarm. $\endgroup$
    – Stian
    Commented Apr 12, 2018 at 19:14

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