Why completely filled orbitals are more stable?

Answer 1

Half-filled orbitals are quite stable because of the electrons' spins being aligned; they resonate and so are stabilised. The same occurs in completely filled shells, except the spins are balanced and negated by the equal numbers spinning in opposite directions; there is no unbalance, and so the orbital is even more stable.

Answer 2

Half-filled orbitals are comprised of electrons that have the same polar spin. This causes the atoms to be able to interact in reactions with other atoms. An atom is generally considered to be unstable if it is an ion or radioactively decaying.

Short answer: open valencies make an atom chemically reactive but not necessarily unstable.

Answer 3

Electrons have a property known as spin. Spin, on the subatomic scale, is not precisely the same thing as spin in the world of visible physical objects, such as a spinning top, although it does have some similarity. Electrons always spin (there is no non-spinning variety) and they always do so at the same speed, and there is only one possible speed (due to quantum mechanical factors) but there are two kinds of spin, clockwise and counterclockwise spin. Since electrons have an electric charge, when they spin, they generate a tiny magnetic field, which naturally has a north pole and a south pole. So, if you line up two electrons so that the north pole of one electron is next to the south pole of the other electron, then opposite poles attract. So, even though electrons repel each other because they have the same charge, they can still have a magnetic attraction toward each other, if they have opposite spin. And any time two electrons are in the same atomic orbital, they will have opposite spin (since an electron can flip over). Now, since both electrons in the orbital are attracted to the positively charged nucleus, that tends to overcome the repulsion that they have toward each other (the nucleus has a larger charge than an electron, except for the hydrogen atom which has only one electron) and if the electrons are also magnetically attracted to each other, then you have greater stability. Subatomic particles go wherever they are attracted most. So electrons form pairs, when possible.

Beyond that, there is the octet rule, stating that an atom is more stable when it has a full outer shell (which is usually 8 electrons, although for hydrogen it can be no electrons at all, as an H+ ion, or it can be two electrons, and several light elements have full electron shells with only two electrons).

I also want to quote this slightly technical explanation, if I may:

The quantum theory of the atom explains the eight electrons as a closed shell with an s2p6 electron configuration. A closed-shell configuration is one in which low-lying energy levels are full and higher energy levels are empty. For example the neon atom ground state has a full n=2 shell (2s2 2p6) and an empty n=3 shell. According to the octet rule, the atoms immediately before and after neon in the Periodic Table (i.e. C, N, O, F, Na, Mg and Al), tend to attain a similar configuration by gaining, losing, or sharing electrons.

Answer 4

Completely filled orbitals are more stable because they have a lower energy level compared to partially filled orbitals. Electrons in completely filled orbitals experience less repulsion from each other, leading to greater stability due to a more balanced electron distribution. Additionally, completely filled orbitals satisfy the maximum number of electrons allowed by the Pauli exclusion principle, further enhancing stability.

Answer 5

half filled electrons are more stable because they spin being aligned.they resonate and get stabilized.the same happens in full filled electrons but they spin nicely and negate .

Answer 6

Fully filled orbitals are more stable. However, a half filled orbital is preferential in regards to the spectroscopic notation. For example, Mo would be [Kr] 4s1 3d5.

Answer 7

As all elctrons are paired up in fully filled orbitals there is no electron is left to pair (react) with other atom/molecule.