There is a 4d sublevel in atomic theory. However, it is important to note that the term “4d” refers to the principal quantum number, which indicates the energy level or shell of the electron. The sublevel, on the other hand, refers to the shape or orbital of the electron within that energy level.
In the electron configuration notation, the energy levels or shells are represented by numbers, such as 1, 2, 3, etc. The sublevels within each energy level are represented by letters, such as s, p, d, and f. In this notation, the 4d sublevel corresponds to the fourth energy level (n=4) and the d orbital shape.
The d sublevel is unique in that it has five different orbitals, labeled as dxy, dxz, dyz, dx^2-y^2, and dz^2. Each orbital can hold a maximum of two electrons, with opposite spins. Therefore, the 4d sublevel can hold a total of 10 electrons.
To understand this concept better, let’s consider the electron configuration of an element with atomic number 22, which is titanium (Ti). Titanium has 22 electrons, and its electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^2 4p^6 5s^2 4d^2.
Here, we can see that the 4d sublevel starts filling after the 3d sublevel, indicating that the 4d orbitals are of higher energy than the 3d orbitals but lower in energy compared to the 5s sublevel.
It is worth mentioning that the concept of sublevels and orbitals is a result of the quantum mechanical model of the atom, which explains the behavior of electrons in terms of wave functions and probability distributions. This model has been extensively tested and has provided accurate predictions of various atomic properties.
The 4d sublevel is a real component of atomic theory, representing the fourth energy level and the d orbital shape. It can hold a maximum of 10 electrons, distributed across its five orbitals.