00:01
In the question we've been given five statements about the molecular orbital theory and we need to figure out which of the following statements is incorrect.
00:10
And the answer to the question is that stable molecules having an even number of valence electrons must be diamagnetic, which is not true.
00:43
So this is incorrect.
00:50
And why am i saying that this is incorrect? because when we look at the example of oxygen so oxygen has the atomic number 8 right and the configuration will be 1 s 2 2 s 2 and 2p 4 so the valence electrons are even when oxygen and oxygen atom will combine to form the o2 molecule again again we get a paramagnetic molecule instead of a diamagnetic molecule.
01:38
And why is it so? so according to huns rule, the two electrons will go into the orbitals one at a time with the same spin.
01:48
So what are we talking about? we are talking about the hunt's rule.
01:58
And for that, let us just look at this diagram, which shows molecular orbits.
02:04
And this is for oxygen molecule and here these are the molecular orbitals and energy is increasing this way so here i have the s orbital and here i have the p orbital and as we know in s we have 1 s2 2s2 and then in p we have 4 electrons so let's say this is my sigma star and this is my sigma sigma...