What is an Atomic Orbital?
Atomic orbitals are mathematical functions that give knowledge into the wave nature of electrons (or sets of electrons) that exist around the cores of atoms. In the fields of quantum mechanics and atomic theory, these mathematical functions are frequently utilized to decide the likelihood of finding an electron (having a place with an atom) in a particular region around the nucleus of the atom.
Note that the term 'atomic orbital' can likewise be utilized to allude to the physical space or physical region around an atom's nucleus in which the likelihood of a particular electron being available is maximum. The presence of an electron in such a region is anticipated by the mathematical form of the atomic orbital.
Note that the qualities of each atomic orbital are reliant upon the estimations of the following quantum numbers:
The principal quantum number (noted by the symbol 'n')
The azimuthal quantum number, otherwise called the orbital precise energy quantum number (signified by the symbol 'l')
The magnetic quantum number (noted by the symbol 'ml')
Besides, it very well may be noticed that each atomic orbital can hold a maximum of two electrons. In totally involved atomic orbitals, for example, the atomic orbitals containing two electrons, every one of the electrons has an equal and opposite turn when contrasted with the other.
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Different Atomic Orbitals and the Relationship Between Different Quantum Numbers which Describe Them
The name of an atomic orbital is normally expressed as far as a combination of the primary quantum number (n) and the azimuthal quantum number (l). The straightforward names of the atomic orbitals and the comparing estimation of the azimuthal quantum number are given below.
The s orbital, in which the estimation of the azimuthal quantum number equals to 0.
The p orbital, in which the estimation of the azimuthal quantum number equals to 1.
The d orbital, in which the estimation of the azimuthal quantum number equals to 2.
The f orbital, in which the estimation of the azimuthal quantum number equals to 3.
The g orbital, in which the estimation of the azimuthal quantum number equals to 4.
The h orbital, in which the estimation of the azimuthal quantum number equals to 5.
It very well may be noticed that the next atomic orbitals can be named one after another in order, precluding the letter 'j' (which is done in light of the fact that specific dialects don't recognize the letters 'j' and 'I'). Subsequently, when l=6, the name of the atomic orbital will be 'I' and when l=7, the name of the atomic orbital will be 'k'.
When naming a particular atomic orbital, the estimation of the essential quantum number must be added as a prefix to the sequential description of the azimuthal quantum number. Note that the estimation of the azimuthal quantum number is subject to the estimation of the important quantum number. For some random estimation of 'n', the estimation of 'l' can range from zero to (n-1). For example, if the estimation of 'n' is equal to 3, the potential estimations of 'l', which range from zero to (3-1), are 0, 1, and 2. The names of these atomic orbitals would then be 3s for n=3, l=0; 3p for n=3, l=1; and 3d for n=3 and l=2. It can likewise be noticed that it isn't feasible for the 3f orbital to exist since that would require the estimation of 'n' and 'l' both to be equal to 3, which is absurd since the estimation of the azimuthal quantum number should consistently be lower than that of the key quantum number.
Table of All the Possible Atomic Orbitals in Which the value of ‘n’ Ranges from 0 - 5
FAQs on Atomic Orbitals
1. What is an atomic orbital in chemistry?
An atomic orbital is a mathematical function, known as a wave function, that describes the three-dimensional region around an atom's nucleus where there is the highest probability of finding an electron. Unlike the fixed paths suggested by older models, an atomic orbital represents a probability cloud whose shape and energy are defined by a specific set of quantum numbers.
2. What are the four main types of atomic orbitals covered in the CBSE syllabus?
The four fundamental types of atomic orbitals that students learn about are named s, p, d, and f. Each corresponds to a specific shape and is associated with the azimuthal quantum number (l):
- s-orbital (l=0): Has a spherical shape.
- p-orbital (l=1): Has a dumbbell shape with two lobes.
- d-orbital (l=2): Has more complex shapes, mostly resembling a cloverleaf or double dumbbell.
- f-orbital (l=3): Has even more intricate and multi-lobed shapes.
3. How are atomic orbitals like 1s, 2p, and 3d named, and what do the numbers and letters signify?
The name of an atomic orbital provides two key pieces of information based on quantum numbers:
- The number at the beginning (e.g., the '1' in 1s or the '3' in 3d) represents the principal quantum number (n). It indicates the main energy level or shell of the electron.
- The letter (e.g., 's' or 'd') represents the azimuthal quantum number (l). It defines the subshell and determines the characteristic shape of the orbital (s for l=0, p for l=1, d for l=2).
Therefore, a '2p' orbital is in the second energy level (n=2) and has a dumbbell shape (l=1).
4. Why can any single atomic orbital hold a maximum of only two electrons?
An atomic orbital can hold a maximum of two electrons due to the Pauli Exclusion Principle. This fundamental rule of quantum mechanics states that no two electrons in the same atom can have the exact same set of four quantum numbers (n, l, ml, and ms). Since any single orbital has fixed values for n, l, and ml, the two electrons occupying it must have opposite spin quantum numbers (ms), which are denoted as +1/2 and -1/2. This limits the orbital's capacity to two electrons with opposite spins.
5. What is the main difference in shape and electron probability between an s-orbital and a p-orbital?
The primary difference lies in their geometry and directionality. An s-orbital is spherically symmetrical, meaning the probability of finding the electron is the same in all directions at a given distance from the nucleus. In contrast, a p-orbital is dumbbell-shaped and has a specific orientation along one of the x, y, or z axes. It has two lobes where electron probability is high, separated by a nodal plane at the nucleus where the probability of finding the electron is zero.
6. Why are there three p-orbitals but five d-orbitals for a given principal energy level?
The number of orbitals in a subshell is determined by the magnetic quantum number (ml), which specifies an orbital's orientation in space. The possible values of ml range from -l to +l.
- For a p-subshell (l=1), the possible ml values are -1, 0, and +1. These three distinct values correspond to three separate p-orbitals (px, py, pz), each oriented along a different axis.
- For a d-subshell (l=2), the possible ml values are -2, -1, 0, +1, and +2. These five distinct values correspond to the five d-orbitals with different spatial orientations.
7. How does the concept of atomic orbitals explain the structure of the modern periodic table?
The structure of the periodic table is a direct consequence of how electrons fill atomic orbitals according to their energy levels. The table is divided into blocks based on the subshell of the highest-energy, or differentiating, electron:
- s-block (Groups 1-2): The final electron enters an s-orbital.
- p-block (Groups 13-18): The final electron enters a p-orbital.
- d-block (Groups 3-12): The final electron enters a d-orbital. These are the transition metals.
- f-block (Lanthanides/Actinides): The final electron enters an f-orbital.
This orbital-based arrangement explains the periodic recurrence of chemical properties.
