Atomic orbital consists of three-dimensional space around the nucleus of an atom where an electron is likely to exist. It relates to the mathematical functions to express the wave nature of electrons in an atom. A mathematical calculation can be done to find out the probability of an electron in a specified region around the nucleus of the atom.
An atom may contain a significant number of orbitals based on their size, shape, or orientation. Narrower orbitals generally hold high-density electrons close to the nucleus. The electrons in orbitals can be indicated by the square of the orbitals wave function to express the creation of boundary surface diagrams.
Atomic Orbital Definition
It represents the specified regions where electrons have the highest probability of being found rather than being in one specific place. It can be called the shell model or nuclear shells. The specific position of electrons is generally calculated by following the rules of quantum mechanics. The removal of an electron from an atom completely depends on which orbitals the electron is in.
According to the quantum mechanical model, the size and shape of orbital characteristics depend on the quantum numbers. The energy of each electron in orbitals can be determined by calculating the values of quantum numbers.
The shape and structure of orbitals are complex which can explain the various properties of matter. For example, the fulfillment of electrons in atomic orbitals represents a chemically inert condition like neon. Another example may be considered when atoms want to take part in chemical reactions for the shortage of electrons on their orbitals like sodium, potassium, etc.
Orbital Examples
The 3s2 orbital contains two electrons and it has the principal quantum number n=3 with an angular momentum quantum number ℓ = 0.
The 3p6 contains six electrons and it has the principal quantum number n=3 with an angular momentum quantum number ℓ = 1.
The 3d10 contains ten electrons and it has the principal quantum number n=3 with an angular momentum quantum number ℓ = 2.
Properties of Electrons in Orbital
Electrons in the orbital show the particle and wave properties. They show the particles and some characteristics of waves which are discussed below:
Particle Properties
Electrons in orbitals contain particle-like properties, such as a single electron contains only one electrical charge. There presence an integer number of electrons around the nucleus of an atom. These electrons can move between orbitals like particles. It can be considered for example that a photon of light when absorbed by an atom, only a single electron changes its energy level.
Wave Properties
Electrons in orbitals behave like waves at the same time. For this reason, it is unable to pinpoint the location of an electron. It may outline the probability of finding one within a region described by a wave function. When electrons are present at the lowest energy level, they show the fundamental frequency of a vibrating string. The electrons have higher energy levels showing harmonic string.
Atomic Orbital Types
There are four different types of atomic orbitals namely s, p, d, and f. These orbitals are generally represented by the proper combination of letters and numerals, such as 1s, 2s, 2p, 3s, 3p, 3d, etc. The numerical values indicate the principal quantum number (n). This quantum number shows the energy levels and their relative distance from the atomic nucleus. The s, p, d, and f letters represent the shape of atomic orbitals.
There may presence of a maximum of two electrons in each orbital based on the opposite spin characteristic. The location of electrons from the nucleus may increase when the energy levels of the atom increase. As a result, the size of the atomic orbital is bigger than before. The subshell of each atomic orbital depends on the values of magnetic quantum number (ml) which ranges from -ℓ to +ℓ, including zero, where ‘ℓ’ stands for azimuthal quantum number.
Diagram of orbitals
The shape of s-orbitals
The shape of s-orbitals looks like a sphere based on the boundary surface diagram. There having two-dimensional spherical symmetric nucleus remains in the center. So the most probable electrons are being found at a given distance equal in all the directions in s-orbitals. The size of s-orbitals is generally increased when the value of the principal quantum number (n) is increased such as 4s > 3s> 2s > 1s.
This spherical orbital generally holds up a maximum of two electrons. The lowest s-orbital is the 1s which can hold one or two electrons. The nodal point can be found in s-orbitals where no chance of locating the electron. There exist two nodes namely radial nodes and angular nodes. The absence of electrons from the nucleus is generally calculated by the radial nodes, while the changes in orientation can be calculated by the angular nodes.
The shape of p-orbitals
It is generally dumbbell-shaped and has the same size, shape, and energy where the nodes are located at the center of the nucleus. It consists of three orbitals which occupy a maximum of six electrons. They are generally made up of two parts known as lobes. These lobes are found on either side of the plane that runs across the nucleus. The two lobes intersect with each other at a plane where the existence of electrons is nil.
There exists the orientation of the lobes along the x, y, or z-axis, and can be represented by the names 2Px, 2Py, and 2Pz. The n2 formula is used for calculating the number of nodes. It can be found the increases in size and energy like 4p > 3p > 2p based on the increases of principal quantum number values.
The shape of d-orbitals
The d-orbitals depend on the value of the magnetic orbital quantum number which is generally given as (-2,-1, 0, 1, 2). There exist five d-orbitals designated as dxy, dyz, dxz, dx2–y2, and dz2. The shapes of dxy, dyz, dxz, dx2–y2 orbitals are almost similar to each other but the shape of dz2 orbital is different. The energy of these orbitals is almost the same.
The shape of f-orbitals
The f-orbitals have a dispersed shape. The minimum value of a principal quantum number is 4 for this orbital. The azimuthal quantum number value l=3 for the f orbital. The magnetic quantum number values for f- orbitals are (-3,–2, –1, 0, +1, +2, +3).
Degenerate Orbitals
These orbitals contain the same energy but have a different orientation in space around the atomic nucleus. This characteristic cannot be affected in the presence of an external electric or magnetic field. This property can be broken for d and f orbitals by applying an external electric or magnetic field to the system. Few orbitals contain higher energy, and others have lower energy. The 3-fold degenerate state of orbitals is found for p-orbitals and the 5-fold degenerate state of orbitals is found for d-orbitals.
Frequently Asked Questions (FAQs)
What do you mean by orbitals in chemistry?
Orbitals contain three-dimensional space around the nucleus of an atom where the electrons can exist easily.
What are the types of orbital?
There are mainly four types of atomic orbitals namely s,p,d, and f orbitals.
Why is it called orbitals?
This atomic characteristic was first invented by Robert S. Mulliken in 1932 as short for the one-electron orbital wave function.
How do orbitals work?
It has a close connection with atomic theory and quantum mechanics to express the wave-like characteristics of either one electron or a pair of electrons in an atom.
What is the main difference between a shell and an orbital?
A shell contains various number subshells of the same quantum number. Orbitals are able to contain two electrons each.
Why are orbitals named SPDF?
The s, p, d, and f orbitals represent the sharp, primary, diffuse, and fundamental associates, particularly the spin-orbital interaction.
How many electrons are there in s, p, d, and f orbitals?
There is one orbital in a subshell, three orbitals in the p subshell, five orbitals in the d subshell, and seven orbitals in the f subshell. Each orbital can hold up to two electrons by following the Pauli Exclusion principles. So it can be noted that the s subshell contains two electrons, the p subshell contains six electrons, the d subshell contains ten electrons, and the f subshell
