Which has the highest energy in the 3D or 4s energy layer of the hydrogen atom?

As shown in the figure, 4s and 3d, although they are degenerate (degenerate are equivalent for different atomic numbers), they appear on the 4th main layer at the same time, but they are also interleaved, that is, they themselves belong to the 4 main layer and the 3 main layer respectively. Under normal circumstances, the electrons must meet the order of ranking from the lower energy level to the higher energy level, so the energy of 4 should be higher than 3, but just because 4s and 3d are degenerate, due to the interaction between electrons in an atom, and the 3 energy level should appear in the position of the 4 energy level, it proves that its 3d energy must be higher than 4s, which is the reason why the energy of 3d is greater than 4s as shown in the figure below.

However, the electrons of the hydrogen atom are 1s themselves, that is to say, 4s and 3d are the positions reached by the electrons of hydrogen after being excited, and in this case these two positions are not affected by the interaction between the electrons, according to the law that the electrons must meet the order of ranking from the lower energy level to the higher energy level, the energy of the 4s electrons of the hydrogen electron is greater than 3d

Quantum mechanics studies have shown that electrons outside the nucleus can only be in certain energy-specific "orbits". The energy possessed by the electrons moving in these "orbitals" is discontinuous.

For example, the energy of an electron for an atom of h is either or divided by n squared, and n is the so-called number of electron layers, or principal quantum number. Normally, electrons will orbit in the orbital with the lowest energy, and the energy of the electrons to the hydrogen atom is. But when electrons gain external energy, it is possible to run to higher energy orbits.

In this case, the energy of the electron may be divided by n squared, not any value in between.

For non-hydrogen atoms, studies have shown that the energy of several electrons in the same layer is not the same, which is manifested in the different range of electron motion (that is, the shape of the electron cloud we call different), in order to distinguish these electrons, people have proposed to describe the range of motion of these electrons by s, p, d, f. So that the energy of the electrons can be distinguished by the number of electron layers and the shape of the electron cloud.

For different atoms, the relative magnitude of the energy of the 3D and 4S energy layers is different, I don't remember the specifics. But that's not about the problem. Because the hydrogen atom we're talking about is a special case.

In the hydrogen atom, it is found that when the electrons move on any layer, its electron cloud is always spherically symmetrical, and there is no electron cloud like p, d, f. That is, to describe the energy state of the electron motion in a hydrogen atom, only n one parameter is sufficient.

Therefore, the landlord's question itself is problematic, the concept that there is only an electron shell for hydrogen atoms, and there is no concept of s, p, d, f. If you have to follow the concept of s, p, d, and f in other atoms, then it is on the same layer that the energies of these orbitals are averaged to each other, and the shape of the orbitals is also averaged (mathematically it can be proved that p, d, and f are spherically symmetrical when averaged). This phenomenon is called degeneracy in spectroscopy and quantum mechanics.

So the answer to the landlord's question is: electron energy 4s>3d.

As the atomic number increases, the difference between the two becomes smaller and smaller, and after reaching a certain ordinal number (I can't remember what I just said is referring to this ordinal number), the energy of 3d is higher than that of 4s.

By the way, it is precisely because the orbital energy structure of the hydrogen atom is relatively simple that Bohr's old quantum theory can explain the spectrum of the hydrogen atom relatively satisfactorily. For slightly more complex HE atoms, Bohr's theory immediately fails.

Energy level interleaving problem: s, p, d, f, g, etc. are recorded as values represented by 0, 1, 2, 3, 4, etc., respectively, and the level of orbital energy is the principal quantum number plus the values represented by s, p, d, f, g, etc., if the obtained value is large, the orbital energy is high, and vice versa; If the values are equal, the orbital energy of the orbital with the largest principal quantum number is high.

For example, 3d=3+2=5, 4s=4+0=4, 5 4, so the 3d orbital energy is greater than 4s

The principal quantum number n is used to describe the distance from the nucleus in the region with the highest probability of electron occurrence in an atom, or it determines the number of electron shells. Thanks!

Xu Guangxian Rules:

1) Unfilled electrons: n+ (n is the principal quantum number, l is the angular quantum number.)

3d 3+ =

4s 4+ unfilled electron energy level order according to Pauling energy level diagram (3d>4s)2) after the electrons are filled: n+ (n is the principal quantum number, l is the angular quantum number.

3d 3+ =

4s 4+ fill in the electron energy level order according to the Cotton energy level diagram (3d<4s) 3) The owner of the building asked that after filling in the electrons, the essential reason is that the 3d electrons are in the inner layer, which has a shielding effect on the 4s electrons, which makes the 4s electron energy increase.

The energy level of the outer shell electrons of the ion is determined by (n+worth, magnitude, 4s=4, 3d= so 4s is greater than 3d

Due to the phenomenon of "energy level interlacing", there is a situation where electrons fill in the outermost NS first, and then fill in the (n-1)d of the secondary outer shell.

The staggered liquid state refers to the phenomenon that the energy of some orbitals with a large number of electron layers is lower than the energy of some orbitals with a small number of electron layers. For example, the energy of 4s is smaller than that of 3d, and the 3d orbital should be filled with 4s before filling the electrons.

The arrangement of electrons outside the nucleus of the vast majority of elements follows the "principle of construction", which can be found in the images in the textbook.

3 all d

The hydrogen atom is just one electron filled with the 1s layer, there is no inter-electron energy level interlacing, and the energy of each orbital only depends on the principal quantum number n, that is, the larger the n, the higher the energy, so 3d<4s.