Atomic Orbitals – Definition and Detailed Explanation with Examples

What is an Atomic Orbital?

An atomic orbital is a three-dimensional region of space around an atom in which an electron is likely to be found. The possible atomic orbitals in which the value of ‘n’ ranges from 0 – 5 are as follows:

S orbital: n = 0
P orbital: n = 1
D orbital: n = 2
F orbital: n = 3
G orbital: n = 4
H orbital: n = 5

Different Atomic Orbitals and the Relationship Between Different Quantum Numbers which Describe Them

The quantum numbers that describe atomic orbitals are:

• n- the principal quantum number
• l- the orbital quantum number
• ml- the magnetic quantum number
• ms- the spin quantum number
• The n- principal quantum number is the main determinant of an orbital’s size and energy. The higher the n- value, the larger and higher-energy the orbital.
• The l- orbital quantum number determines the shape of the orbital. It can have the values 0-n-1, where n is the principal quantum number.
• The ml- magnetic quantum number indicates the orientation of the orbital in space. It can have the values -l to +l, where l is the orbital quantum number.
• The ms- spin quantum number indicates the orientation of the electron’s spin within the orbital. It can have the values +/-1/2.
• An atomic orbital is a mathematical function that describes the wave-like behavior of an electron around a nucleus. The three types of atomic orbitals are s, p, and d. Each type of orbital has a different shape and can hold a different number of electrons.
• S orbitals are spherical and can hold a maximum of two electrons. P orbitals are three-dimensional and can hold a maximum of six electrons. D orbitals are five-dimensional and can hold a maximum of ten electrons.
• The shapes of atomic orbitals are determined by the quantum numbers of the electron. The principal quantum number, n, determines the size and shape of the orbital. The angular momentum quantum number, l, determines the shape of the orbital. The magnetic quantum number, ml, determines the orientation of the orbital.
• The electron in an atomic orbital can spin in either a clockwise or a counterclockwise direction. This is called the spin quantum number, ms. The electron can have a total of two spin states, ms = +1/2 or ms = -1/2.
• The electron in an atomic orbital can also move up or down in energy. This is called the orbital energy. The higher the energy of the orbital, the higher the energy of the electron.