oxygen and nitrogen

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oxygen and nitrogen

Postby vicenteruelos3 » Wed Nov 01, 2017 11:35 pm

why is oxygen and nitrogen switched for ionization energy and not for electronegativity if electonegativity is based on ionization energy??

Harrison Wang 1H
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Re: oxygen and nitrogen

Postby Harrison Wang 1H » Thu Nov 02, 2017 1:09 am

The ionization energy of oxygen is higher than that of nitrogen because nitrogen has half asymmetry in its p shell while oxygen has a full first orbital. The higher electron affinity of oxygen compared to nitrogen compensates for this deficiency when talking about electronegativity.

Austin Ho 1E
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Re: oxygen and nitrogen

Postby Austin Ho 1E » Thu Nov 02, 2017 10:51 pm

Electronegativity describes the tendency of an atom to pull electrons toward itself within a species. This is related to the effective nuclear charge - in the molecule H2O for instance, Oxygen has higher electronegativity than the Hydrogens, and the covalent bond is shared unequally as Oxygen pulls the shared electrons toward itself more.

The reason why Oxygen has a lower Ionization Energy than Nitrogen is due to its 2p4 structure. The fourth electron added cannot be added to an empty subshell; it is paired with an electron already in the p subshell. Due to the electron-electron repulsion, this takes more energy than we would expect. Thus, it takes less energy than we would expect to remove that same electron.

In general, O has higher electronegativity than N because of the increased number of protons and stronger effective nuclear charge.

Aliza Ajmal 1D
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Re: oxygen and nitrogen

Postby Aliza Ajmal 1D » Sun Nov 12, 2017 9:20 pm

To add to the other responses, remember Hund's rule. You need to fill all the orbitals with one electron (fill all with the up pointing arrow representing the spin up of the electron) before you double up on electrons. Then, make sure the 2 electrons in each orbital have opposite spins (drawn arrows facing opposite directions). If you write out the 2p subshell with its 3 orbitals and fill each with an electron in accordance to the orbital, you will be able to visualize this concept better.

Nitrogen has a higher ionization energy because it is more stable than oxygen. Atoms that are already stable require more energy to remove an electron because they do not want to be unstable. The reason why oxygen has a lower ionization energy is because it is less stable; it has an awkward extra electron making 2 electrons unpaired in the 2p orbitals. It's more stable to have all the orbitals half-filled with electrons, therefore oxygen is more willing to get rid of this extra awkward electron.

I hope this helps!

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