Question

What is the order for third ionization enthalpy for second period elements??

Answer 1

Dear Student,

The element with +3 valency will have the least third ionisation enthalpy i.e. boron will have least ionisation enthalpy.
Be will have the highest third ionisation enthalpy as configuration in Be²⁺ in fulfilled and so it will not easily lose electron.
After B, N will have the second lowest ionisation energy as after removal of 3 electrons, it will achieve fulfilled 2s^​2 configuration.
So, the order will be Be > Li > O > C > N > B
Li will have higher ionisation enthapy than O as in Li electrons are removed from the inner shell. O being more electronegative has higher IE than C.