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Electronegativity

Why does oxygen have a greater electronegativity?

This is the problem I am facing and why I am struggling to accept that fact that it does:

Despite oxygen having a greater nuclear charge than hydrogen, it ultimately has an extra energy level, and so the valence electrons are further away from the nucleus and experience more shielding, so they experience less of the attractive forces of the nucleus, and so less attracted to it. So shouldn't the electronegativity be lower? After all electronegativity is the ability of an atom to attract a pair of electrons towards itself in a covalent bond...

Sorry If I am bothering you
Original post by sweetescobar
Why does oxygen have a greater electronegativity?

This is the problem I am facing and why I am struggling to accept that fact that it does:

Despite oxygen having a greater nuclear charge than hydrogen, it ultimately has an extra energy level, and so the valence electrons are further away from the nucleus and experience more shielding, so they experience less of the attractive forces of the nucleus, and so less attracted to it. So shouldn't the electronegativity be lower? After all electronegativity is the ability of an atom to attract a pair of electrons towards itself in a covalent bond...

Sorry If I am bothering you


The OH bond length is 96pm
If (and only if) the electron pair were exactly half way between the two atoms the force of attraction from the nucleus for each electron would be proportional to 1 x 1/48 units = 0.0208
The attraction for the oxygen nucleus (ignoring shielding) would be 0.167 units
For both nuclei to attract equally the electrons would have to be at about 10pm from the hydrogen nucleus and 85 pm from the oxygen nucleus.
The atomic radius (the 1s orbital) of hydrogen is 53 pm
So according to the laws of electrostatics, for an equal attraction the electrons would have to be at a position from the nucleus five times smaller than the atom itself!
Ok, but If I had an A level question on this how would I explain this in, well, a level terms.

I am very sorry if I am bothering you.
oxygen is more electronegative than hydrogen because an oxygen atom has a greater nuclear charge than hydrogen, which outweighs the (only slightly) more shielding in oxygen. so the oxygen atom has a greater tendency (than hydrogen) to attract the pair of electrons in a covalent bond

this page on chemguide gives a decent explanation of electronegativity:
https://www.chemguide.co.uk/atoms/bonding/electroneg.html

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