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Atomic orbital

physical science Maturity 11-13 Next article →

{

"text": "An atomic orbital is a mathematical function used in quantum mechanics. It describes the location and wave-like behavior of an electron within an atom. Instead of defining a precise path, an orbital describes the charge distribution around a nucleus. Scientists use these functions to calculate the probability of finding an electron in a specific region. This concept is a fundamental building block of the atomic orbital model. This modern framework helps us visualize the submicroscopic behavior of electrons in matter.

Schrodinger model of the atom
Schrodinger model of the atom

\n\nTo understand how orbitals work, we must look at wave-particle duality. Electrons do not orbit a nucleus like planets orbiting a star. Instead, they exist as standing waves. This means an electron does not occupy a single point in space. Its charge is smeared out in a continuous distribution. This distribution is proportional to the squared magnitude of the electron's wave function. You might imagine an orbital as a large, oddly shaped atmosphere surrounding a tiny planet.

Hydrogen Density Plots
Hydrogen Density Plots

\n\nEach orbital is defined by a specific set of three quantum numbers. The first number, $n$, corresponds to the electron's energy level. The second number, $l$, represents the orbital angular momentum. The third number, $m_l$, is the magnetic quantum number. This last value represents the angular momentum projected along a chosen axis. These numbers allow scientists to characterize the specific state of an electron. Orbitals are often categorized into types based on their angular momentum. These include s, p, d, and f orbitals.

Electronic levels
Electronic levels

\n\nThere are different mathematical forms used to describe these orbitals. Hydrogen-like orbitals are exact solutions to the Schrödinger equation for an atom with one electron. These functions decay as $e^{-r}$ and contain radial nodes. Slater-type orbitals (STOs) are also used for atoms with many electrons. STOs do not have radial nodes and decay similarly to hydrogen-like orbitals. For molecules with three or more atoms, scientists often use Gaussian-type orbitals. These decay as $e^{-\alpha r^2}$ and are very useful in computer calculations.

Neon orbitals
Neon orbitals

\n\nOur understanding of the atom has evolved through many historical discoveries. In 1897, J. J. Thomson discovered the electron, proving atoms were composite. In 1904, Hantaro Nagaoka proposed an orbit-based hypothesis for electron behavior. Ernest Rutherford improved these ideas around 1911 by explaining the nucleus. Around 1913, Niels Bohr suggested electrons revolve around a nucleus with definite angular momentum. Finally, in 1932, Robert S. Mulliken introduced the term \"orbital.\" He used it as a shorthand for the one-electron orbital wave function.

Bohr atom model
Bohr atom model

\n\nAtomic orbitals are essential for explaining the structure of the periodic table. The table contains repeating blocks of 2, 6, 10, and 14 elements. These patterns arise from the total number of electrons that fill complete sets of s, p, d, and f orbitals. For example, s orbitals hold 2 electrons, while p orbitals hold 6. This relationship creates the natural periodicity seen in chemical elements. However, the order of filling can be complex. In certain atoms, like chromium, the energies of different sub-shells become very similar.

Atomic-orbital-clouds spdf m0
Atomic-orbital-clouds spdf m0

\n\nOrbitals also help us visualize the process of excitation. An atomic spectral line occurs when an electron undergoes a quantum leap between states. This transition can be described as an electron moving from an occupied orbital to an unoccupied one. While we often use the independent-particle model, electrons are actually fermions. They follow the Pauli exclusion principle, meaning no two electrons can be identical. An orbital can hold a maximum of two electrons, provided they have opposite spins. This complex interplay of waves and particles defines the chemical world.",

"media": [

"File:Schrodinger model of the atom.svg",

"File:Hydrogen Density Plots.png",

"File:Electronic_levels.svg",

"File:Neon orbitals.png",

"File:Bohr atom model.svg",

"File:Atomic-orbital-clouds spdf m0.png"

]

}

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🖼️ Images & Media (56)
File:Neon orbitals.png
Neon orbitals.png
File:Hydrogen Density Plots.png
Hydrogen Density Plots.png
File:Atomic-orbital-clouds spdf m0.png
Atomic-orbital-clouds spdf m0.png
File:Bohr atom model.svg
Bohr atom model.svg
File:Electronic_levels.svg
Electronic_levels.svg
File:Orbital p1-px animation.gif
Orbital p1-px animation.gif
File:Atomic-orbital-cloud_n6_l0_m0.png
Atomic-orbital-cloud_n6_l0_m0.png
File:Sr core-electron orbitals for Wiki.jpg
Sr core-electron orbitals for Wiki.jpg
File:Schrodinger model of the atom.svg
Schrodinger model of the atom.svg
File:S1M0.png
S1M0.png
File:S2M0.png
S2M0.png
File:P2M0.png
P2M0.png

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