How Many Electrons In An Atom Could Have These Sets Of Quantum Numbers

Quantum Numbers and Electron Configuration


How Many Electrons In An Atom Could Have These Sets Of Quantum Numbers

Do you know about quantum? how many electrons in an atom could have these sets of quantum numbers? Quantum numbers are numbers that indicate the position or position of electrons in an atom. Quantum numbers consist of major quantum numbers,  magnetic quantum numbers, and spin quantum numbers.


  1.  Primary quantum numbers represent energy levels.
  2.  The azimuthal quantum number expresses the shape of the orbitals, in short, how many orbitals there are.
  3.  Magnetic quantum numbers express the orientation of orbitals in three-dimensional space, in short, which room the electron is in.
  4.  Quantum spin numbers indicate the direction of electrons in the atom if in short the direction of the electron in the room what to do anyway.

The main quantum number (n) represents the level of main energy that electrons have in an atom. The main quantum number is never zero. The main quantum numbers start from 1,2,3,4 etc. by using the letters K, L, M, N, etc.


n = 1, electrons are in the skin K

n = 2, electrons are in the skin L

n = 3, electrons are in the skin M

n = 4, electrons are in the skin of N

note: the greater the “n”, the greater the electron’s distance from the nucleus.

azimuth/momentum quantum numbers (l) are related to the number of subshells. This value describes the subshell where the electrons are located. For subshell s, p, d, the values are 0.1, 0.3, respectively. The azimuthal quantum number (l) is related to the main quantum number (n). If n = 1, then l = 0; if n = 2, then l = 0, 1; if n = 3, then l = 0,1,2.

Atomic Orbital Shape

Orbital s

The 1s orbital has the highest electron density in the nucleus where the density decreases slowly after moving away from the nucleus. Orbital 2s has a high electron density. Between the two regions, there are spherical vertices, where the probability of finding electrons decreases to zero (ψ2 = 0).

Orbital p

The p orbitals have three types of spatial orientation, px, py, and pz and three ml values namely −1, 0, or +1. The three p orbitals are located perpendicular to the x, y, and z-axis of the Cartesian coordinates of the same shape, size, and energy.

Orbital d

Orbital d is an orbital with l = 2. Orbital d has five types of orientation, as there are five possible ml values, namely −2, −1, 0, +1, or +2. Four of the five d orbitals, among others dxy, dxz dyz, and dx2 − y2 have four lobes like the shape of a cloverleaf. The fifth d orbital, dz2, has two main lobes on the z-axis and one donut-shaped part in the middle.

Orbital f

Orbital f is an orbital with l = 3. Orbital f has seven types of orientation, as there are seven possible ml values (2l + 1 = 7). The seven f orbitals have complex shapes with multiple lobes.

Quantum number spin (s) 

The quantum spin states the angular momentum of a particle. Spin has the symbol “s” or often written as ms (magnetic spin quantum number). An electron can have a spin quantum number s = +1/2 or -1/2.

The positive or negative value of the spin indicates the spin or rotation of the particle on the axis. For example, for the value s = + 1/2 meaning counterclockwise (upward), while s = -1 / 2 means clockwise (downward). Half value is taken because there are only two orientation opportunities, namely top, and bottom. Thus, the chance of going up is 50% and the chance of going down is 50%.

And remember the direction of the atom fills the existing rooms in the beginning with an upward direction which means positive until when the room is full of upward direction, it is filled with downward direction. Means that if the electron ends in the upper direction then the value is + ½ and if in the bottom direction the value is ½. Continue to electron configuration …

Electron Configuration

How many electrons in an atom could have these sets of quantum numbers? After understanding the relationship of the existence of electrons in atoms with orbitals in the atomic theory of quantum mechanics, the following will be discussed electron configurations, namely the arrangement of electrons in orbitals in the multi-electron atomic shells. The rules in determining electron configurations based on orbitals include:

  1. Aufbau principle: Electrons occupy the orbitals starting from the lowest energy level, starting from 1s, 2s, 2p, and so on as the sequence of subshells seen in the following figure.
  2. Pauli’s prohibition principle: There are no two electrons in one atom that have the same four quantum numbers. Each of the maximum orbitals is filled with 2 electrons that have opposite spins (ms = + ½ and ms = −½).
  3. Hund Rules: If there are orbitals with the same energy level, the electron configuration with the lowest energy is the number of unpaired electrons with the most parallel spin.

Those are the information about how many electrons in an atom could have these sets of quantum numbers? If you like this article, don’t forget to give it to your friends. Thank you.