The First Ionisation Energy Of Oxygen Is Less Than That Of Nitrogen. Which Of The Following Is The Correct Reason For This Observation?

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The first ionisation energy of oxygen is less than that of nitrogen. Which of the following is the correct reason for this observation?


Correct option is

Greater interelectron repulsion between two electrons in the same p-orbital counter balances the increase in effective nuclear charge on moving from nitrogen to oxygen  


The electronic configuration of nitrogen is

                     7N = 1s2, 2s2, 2p3


Due to the presence of half-filled p-orbitals a large amount of energy is required to remove an electron from nitrogen. Hence, first ionisation energy of nitrogen is greater than that of oxygen.

The electronic configuration of oxygen is  

                     8O = 1s2, 2p2, 2p4


The other reason for the greater IP of nitrogen is that in oxygen, there is a greater inter electronic repulsions between the electrons present in the samep-orbital which counter balance the increase in effective nuclear charge from nitrogen to oxygen. 



Which of the following sequence correctly represents the decreasing acidic nature of oxides?


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The set representing the correct order of ionic radius is


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The correct order of ionisation energy of C, N, O, F is


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