Rethinking the Molecule

So just finishing teaching the chemistry component of the 2nd year course, and we are doing bonding. I am sure that the class got the fact that Metals & Non Metals are attracted due to Ionic Charges.  These Electric charges come from different atoms 'trading' electrons for their own purpose (to have full outer electron orbits) and those that donate an electron become positive and those that get the electron become negative.

Covalent bonding is the sharing of electrons, and I have some nice diagrams of some common simple molecules, CH4 Methane, Water H2O and the Halogens F2 

 .... but I always struggled to accurately represent O2 in Bohr diagram form. I have seen anything that manages to actually get 8 electrons on each outer shell while only not exceeding the 16 electron total that both atoms must manage between them.  I used to explain it in terms of sub-orbits the s-shell and the 3 p-shells .... but I don't know why this is just junior (<16 yo) science. 

Then today as I set the class the various tasks to draw these bonding diagrams .... I got 2 separate answers that knock me back on my heels .... 2 answers, from 2 lads, that sit decently far apart that the coincidence was not explainable by eyesight.

Well anybody got any thoughts on this ? 

I was smacked ... these guys have the smarts for quite a lot of things.  Well done JD & LC