Question

The ionization potential of noble gases is lower with respect to nitrogen.Explain with reason.

Answer 1

Answer:

This question is also part of a bigger question: why would first IE increase across any Period (and is the greatest for noble gases)?

We can use the concept of effective nuclear charge.

Across the Period, proton number increases hence nuclear charge increases. This means there is a greater positive charge of the nucleus attracting the electrons to prevent them from being lost from the atom.

Similarly, the number of electrons increase but since they are added to the same principal quantum shell, these added electrons can't shield each other.

So shielding effect or screening effect is the same. Shielding effect is the reduction in the attraction between nucleus and valence electrons due to the inner shells acting as a barrier.

So we can combine both increase in nuclear charge and constant shielding effect and the effective nuclear charge will increase. This means the attraction between nucleus and valence electrons will be stronger and more energy is required to overcome the attraction and remove the electron. Hence IE will increase and peak for noble gases.

It's good to note that the explanation using “noble gases have full octet electronic configuration so they are stable" is actually a consequence of effective nuclear charge concept and is not accepted as an explanation for A Level Chemistry and above.

Maverick Puah

Chemistry Guru

https://chemistryguru.com.sg

Explanation: