Why half filled and fully filled orbitals of a subshell are more stable as comapared to one fullly filled orbital
and other half filled orbital of same subshell?explain with example.
Answers
Atoms exist in orbitals, and an orbital has two electrons, According to Pauli's exclusion principle, two electrons which exactly identical to each other, hate to be at same place! That is no electrons have the same configuration. So in an orbital which can hold 2 electrons, each electron has an opposite spin. Clockwise and Anti-clockwise which gives it stability. Thats all angular momentum thing conserved here stuff.
Thats the background needed.
Coming to your question,
Now according to Aufbau principle electrons with same spin are filled first. So in a D orbital First five electrons with clockwise spin (say) are filled first. Then the six electron will of anti-clockwise spin which will increase the overall energy of system as electrons with opposite spin repeal each other. Thus we get more stability at fifth electron, or in general at half filled orbital.
Same story at completely filled orbitals as Every electron has an counter-part and everyone is happy.
Another factor to consider is the exchange energy. Electrons love to roam about, in its sub-shell, and an extra odd anti-clockwise electron will just increase the total energy and decreasing stability.
Example--- 1. Nitrogen 14 is the most abundant form of nitrogen and makes up more than 99% of all nitrogen found on Earth. It is a stable compound and is non-radioactive. it has 3unpaired electrons in its valence shell
2. Helium atoms, on the other hand, have two protons and two electrons in the lowest energy level. The lowest energy level is filled with its maximum number of electrons. This is a very stable arrangement, and helium in consequence is an inert gas with few chemical properties.
A stable electron configuration for the representative or main group elements is a noble gas configuration. ... The noble gases are in Group 18 (VIIIA). Atoms of the representative elements achieve a noble gas configuration by gaining or losing electrons and becoming ions, or by sharing electron