What are Quantum Numbers?
by Owen Borville
July 17, 2024
Physics
Quantum numbers are a set of four numbers that describe the complete movement and trajectory of each electron within an atom. Quantum numbers describe the position and energy of the electron in an atom.
These quantum numbers describe the size, shape, and orientation in space of the orbitals in an atom.
Quantum numbers are based on the Bohr model, a one-dimensional model that used one quantum number to describe the distribution of electrons in the atom.
Niels Bohr's model (1913) only focused on the size of the orbit of the electron around the nucleus, which was described by the n quantum number.
Erwin Schrodinger's model (1926) allowed the electron to occupy three-dimensional space, and therefore required three coordinates, or three quantum numbers, to describe the orbitals in which electrons can be found.
The three coordinates that come from Schrodinger's wave equations are the principal (n), angular or azimuthal (l), and magnetic (m) quantum numbers. These quantum numbers describe the size, shape, and orientation in space of the orbitals on an atom.
The principal quantum number (n) describes the size of the orbital. Values=n=1,2,3,4,5,6,7...(cannot be 0)
On the Periodic Table, the principle quantum number (n) is equal to the period (left row) number for elements in the S-block and P-block. For elements in the D-block, n is equal to the period number minus 1, and for elements in the F-block, n is equal to the period number minus 2.
The angular quantum number (l) describes the shape of the orbital. Values=l=0,1,2,...,n-1...(if n=3, l=0, 1, 2)
The magnetic quantum number (m) describes the specific orbital within the subshell and yields the projection of the orbital angular momentum along a specified axis. Values=m=(-l, l)....(if l=2, m= -2, -1, 0, +1, or +2)
A fourth quantum number, the spin magnetic quantum number, (s) describes the intrinsic spin angular momentum of the electron within each orbital and gives the projection of the spin angular momentum S along the specified axis. Values=s=(-s, s) or (+1/2, -1/2)
Therefore, the four principle quantum numbers describe the electron's energy level, sublevel, orbital, and spin.
by Owen Borville
July 17, 2024
Physics
Quantum numbers are a set of four numbers that describe the complete movement and trajectory of each electron within an atom. Quantum numbers describe the position and energy of the electron in an atom.
These quantum numbers describe the size, shape, and orientation in space of the orbitals in an atom.
Quantum numbers are based on the Bohr model, a one-dimensional model that used one quantum number to describe the distribution of electrons in the atom.
Niels Bohr's model (1913) only focused on the size of the orbit of the electron around the nucleus, which was described by the n quantum number.
Erwin Schrodinger's model (1926) allowed the electron to occupy three-dimensional space, and therefore required three coordinates, or three quantum numbers, to describe the orbitals in which electrons can be found.
The three coordinates that come from Schrodinger's wave equations are the principal (n), angular or azimuthal (l), and magnetic (m) quantum numbers. These quantum numbers describe the size, shape, and orientation in space of the orbitals on an atom.
The principal quantum number (n) describes the size of the orbital. Values=n=1,2,3,4,5,6,7...(cannot be 0)
On the Periodic Table, the principle quantum number (n) is equal to the period (left row) number for elements in the S-block and P-block. For elements in the D-block, n is equal to the period number minus 1, and for elements in the F-block, n is equal to the period number minus 2.
The angular quantum number (l) describes the shape of the orbital. Values=l=0,1,2,...,n-1...(if n=3, l=0, 1, 2)
The magnetic quantum number (m) describes the specific orbital within the subshell and yields the projection of the orbital angular momentum along a specified axis. Values=m=(-l, l)....(if l=2, m= -2, -1, 0, +1, or +2)
A fourth quantum number, the spin magnetic quantum number, (s) describes the intrinsic spin angular momentum of the electron within each orbital and gives the projection of the spin angular momentum S along the specified axis. Values=s=(-s, s) or (+1/2, -1/2)
Therefore, the four principle quantum numbers describe the electron's energy level, sublevel, orbital, and spin.