Aarti Gupta
Last Activity: 9 Years ago
Ionisation energy is defined as the energy required to remove an electron from a gaseous atom or ion.
First Ionization energy :- Is the energy required to remove an electron from the gaseous atom.For ex-for the elementM(g)→ M+(g)+ e, first ionization energy is I1.
Second Ionization energy :-Is the energy required to remove an electron from the gaseous ion.
Second Ionization of element M, M+(g)→ M2+(g)+ e, second ionization energy is I2.
It is observed that second ionization energy is greater than first ionization energy for an element because it is harder to remove a negatively charged electron from the positively charged ion.
Now for the above elements- when one electron is removerd from all these elements they will converted to ion and their configuration will become-
Mg[Ne]3s1,Si[Ne]3s23p1,P[Ne]3s23p2and S[Ne]3s23p3
Therefore the increasing order of second ionisation energy will be---
Mg<Si<P<S
The second ionisation energy will be highest for sulphur because of extra- stability of half-filled p orbital on removing of 1 electron.