Degenerate Orbitals and their Concerned Principles
Chemistry is a subject of visualization and learning of concepts on matter and chemical compounds. Here we will learn the basic structure of the atom by understanding degenerate orbitals' meaning and their concerned principles like the Aufbau Principle and Hund's Rule.
The same subshell electron orbitals having the same energy level are known as degenerate orbitals. These degenerate orbitals exist at every moment until not disturbed by the magnetic field. The degeneracy disrupts the application of the magnetic field.
Hunds's Maximum Multiplication Rule
For a given electron configuration, Hund's Rule of Maximum Multiplicity states that the term with maximum multiplicity has the lowest energy. The rule states that, for p, d, and f orbitals, electrons must be paired only if each orbital contains an electron or is singly occupied.
What is Hund's Rule?
Hund's rule of electrons states that degenerate orbitals are filled evenly before electrons are filled in higher energy levels. Three principles explain the process of filling electrons in subsequent levels, namely the Pauli-exclusion Principle, Aufbau Principle, and Hund’s Rule.
Postulates of Hund's Rule:
According to the report:
1. A sublevel consists of single orbitals that are occupied before multiple orbitals can occupy them.
2. An electron occupying single orbitals has the same spin as an electron in multiple orbitals.
A description of Hund's Rule
After entering an orbital, electrons pair with each other. These negatively charged particles repel one another. Because electrons do not share orbitals, their repulsion is minimized.
The spins of unpaired electrons in singly occupied orbitals are the same when we consider the second rule. It's determined by the spin of the first electron in a sublevel what the spin of the other electrons will be. One example in which this would be true is the electron configuration of a carbon atom, which would be 1s²2s²2p². The two 2s electrons will occupy the same orbital, which is consistent with Hund's rule, whereas the two 2p electrons will occupy different orbitals.
What is the Aufbau Principle?
Aufbau’s principle states that electrons are filled in order from lower energy levels to higher energy levels, where the lower energy levels are filled first. This principle helps to predict the type of chemical bond that an atom can form.
Degenerate Orbitals Example
Here is a degenerate orbitals example that will help students to understand the degenerate orbital meaning more clearly.
Example: An atom has four orbitals, namely s, p, d, and f. The p orbital has three orbitals px, py, and pz. All these three orbitals have similar energy belonging to the same orbital (p), hence are called degenerate molecular orbitals. Every orbital at first obtains one electron, then the next electron of opposite spin fills in the same orbital. In the end, three orbitals possess 6 electrons, and the p orbital gets filled.
Explanation of Degenerate Orbitals with Diagram
Let us go through a detailed explanation of degenerate orbitals with a diagram, to have a 3D print of this concept in mind. Electron filling in a 2p orbital involves 2px, 2py, and 2pz. All these orbitals have the same energy level as each other. Similarly, electron filling in a 3p orbital involves 3px, 3py, 3pz. These orbitals have similar energy levels, hence are called degenerate molecular orbitals. Electrons in 4p involve 4px, 4py, and 4pz, these also have a similar energy level as one another; hence these are also degenerate. Now, let us compare these p subshell degeneracies through a graphical representation.
(Image will be Uploaded soon)
Solved Examples
The arrangement of orbitals based on energy is based upon their (n+l) value. The lower the value of (n+l), the lower is the energy. For orbitals having the same values of (n+l), the orbital with a lower value of n will have lower energy.
I. Based upon the above information, arrange the following orbitals in the increasing order of energy.
(a) 1s, 2s, 3s, 2p
(b) 4s, 3s, 3p, 4d
(c) 5p, 4d, 5d, 4f, 6s
(d) 5f, 6d, 7s, 7p
Ans. Based on the meaning of the Aufbau Principle, the solutions are:
(a) 1s < 2s < 2p < 3s
(b) 3s < 3p < 4s < 4d
(c) 4d < 5p < 6s < 4f < 5d
(d) 7s < 5f < 6d < 7p
When 3d orbital is complete, the new electron will enter the
(a) 4p-orbital
(b) 4f-orbital
(d) 4s-orbital
(d) 4d-orbital
Ans. According to the Aufbau Principle definition, the electron will enter from a lower energy shell to a higher energy level. 4p orbital is the next higher energy level than 3d orbital, so the electron will enter into 4p orbital.
Did You Know?
An atom imparts colour in visible light due to the property of empty or incompletely filled degenerate levels.
Aufbau Principle helps to decide the stability of an atom, the half-filled and fulfilled electron orbitals are the most stable.
In the Aufbau principle, the first word is a German word that means building up. In orbitals building up means filling up.
This is all about degenerate orbitals and the principles related to them. Understand the concepts well and study the solved examples to grab hold of the concepts.
FAQs on Degenerate Orbitals
1. What are the Aufbau Principle and Hund’s Rule?
Aufbau Principle is one of 3 major principles that explain the electron distribution in atoms. According to this principle, electrons are filled from lower energy levels to higher energy levels. So, in simple words, the meaning of the Aufbau Principle is that before filling lower energy levels, you can't jump to higher energy levels.
Hund’s rule established by Friedrich Hund provides details about the ground state of a multi-electron atom. This rule states that every orbital must be filled with at least a single electron before filling an orbital with double electrons of opposite spin.
2. What does Hund's Rule Explain with an example?
The electron filling procedure and electronic configuration are decided with the help of Hund's principle. Hund's principle for atomic structure states that every orbital occupies a single electron before the occupancy of double electrons in any orbital. Let us have an example of the quick grabbing of Hund’s rule concept.
The electronic configuration of the Boron atom is 2s² 2p³. There are two paired electrons in an s subshell, and 3 electrons singly occupied in p orbitals. This is because of Hund’s rule as all degenerate molecular orbitals have first single electrons and only then get paired electrons.
3. How can we predict an element's electron configuration?
Atomic electron configurations can be predicted simply using a set of rules.
The electron configuration simply refers to the number of electrons in each orbital. This information is necessary to calculate the number of electrons you'll need. The atomic number + the charge on the ion can be found on the periodic table. If the atomic number is all you get, then you will get the ion's name. Because a periodic table has a particular shape, it's easy.
Elements such as alkali metals and alkaline earth metals have electrons that are closest to the s orbital. Electrons in the highest shell of a molecule have the highest energy, hence they are referred to as valence electrons. The high electrons in the p orbitals are found in the main group of halogens and noble gases (yellow). Its d orbitals are for transition metals, and the f orbitals are for lanthanides and actinides. Each section is composed of 2, 6, 10, or 14 elements, because the s, p, d, and f subshells each have 1,3,5,7 orbitals, with two electrons in each orbital.
Therefore, just by looking at a periodic table, you can write the electron configuration. Continue writing the number of electrons in each subshell until you have the right number total. You would have, for example, 1s²2s²2p⁶3s²3p¹ for Al. The electron configurations of each subshell are indicated with superscripts so that we can calculate their number of electrons.
4. Can you describe non-degenerate and degenerate semiconductors?
In the case of a degenerate semiconductor, the material is so high in doping that it starts to act more like a metal than a semiconductor. This is a degenerate semiconductor with a wide gap. A characteristic of degenerate semiconductors is that the hole concentration remains the same at any temperature. Degenerate orbitals are orbitals with the same energy. Atoms with more than one electron have degenerate orbitals. When electrons fill degenerate orbitals with parallel spins, they do so singly first. In other words, this is the result of an atom's tendency to find the lowest energy state possible
