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Wize University Chemistry Textbook > Quantum Numbers and Electron Configurations

Orbital Filling Diagrams

Radial and Angulor NodesPrevious Section
Electronic Configuration for AtomsNext Section
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Relative Energies of Atomic Orbitals

One-Electron Species

  • For a one-electron species like the hydrogen atom, there is no electron-electron repulsion. Therefore, all the subshells of the same n are degenerate.
  • Orbitals at the same energy level are called degenerate.




Wize Tip
It will be helpful to understand the difference between a shell, a subshell, and an orbital.
We will label these in the diagram above!

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Multi-Electron Species

  • With multi-electron species, there are interactions between electrons (electron-electron repulsion)
  • The energy level diagram of the orbitals looks like this:



Wize Concept
  • S subshells hold a maximum of
    2
    electrons
  • P subshells hold a maximum of
    6
    electrons
  • D subshells hold a maximum of
    10
    electrons
  • F subshells hold a maximum of
    14
    electrons


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The total number of orbitals in a given shell is given by:n2\boxed{\text{The total number of orbitals in a given shell is given by}: n^2}

Example:

If n=2, what is the total number of orbitals in that shell?
  • 22=4
    , circle the
    4
    orbitals that have n=2 above

What if we wanted to know the maximum number of electrons we could have if n=2?

  • We already found that total number of orbitals for this shell (
    4
    )
  • What is the maximum number of electrons we could have in each orbital?
    2
  • Therefore the maximum number of electrons possible when n=2 is
    8

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Rules for Orbital Filling

1) Aufbau Principle

Electrons will always occupy the lowest available energy level first.



Watch Out!
Memorize the order of orbital filling (or just familiarize yourself enough with the periodic table to know the order!): 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p...

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2) Hund’s Rule

Due to electron-electron repulsion, electrons will fill orbitals of the same energy singly before pairing up

Electrons don't want to be next to each other unless they have to be!
Example: Fill out the following orbital diagram for C


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3) Pauli Exclusion Principle

No two electrons in an atom will have the same set of 4 quantum numbers.


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Example: Orbital Filling Diagrams

Draw the orbital diagram for oxygen.


↿⇂↿⇂↿⇂↿↿1s2s2p\begin{array}{ccccc}\boxed{\upharpoonleft\downharpoonright}&\boxed{\upharpoonleft\downharpoonright}&\boxed{\upharpoonleft\downharpoonright}\boxed{\upharpoonleft}\boxed{\upharpoonleft}\\ 1s&2s&2p\end{array}

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Example: Orbital Filling Diagrams

Complete the atomic orbital diagram below for a neutral calcium atom.

Practice: Orbital Filling Diagrams

Which of the orbital diagrams gives the correct electron configuration for an atom of boron, in the ground state?

Practice: Number of Orbitals

How many different atomic orbitals exist where n = 3?

Extra Practice
Quantum Numbers
How many electrons can have the following quantum numbers:
a. n = 4
b. n = 4, ms = + 1/2
Practice: Quantum Numbers and Electronic Configuration
1. Which groups of atoms are diamagnetic in their ground electronic states?
2. What would be the electronic configuration of Na if each orbital could hold 3 instead of 2 electrons? Draw the electronic configuration assuming all other rules are valid.
3. What is the maximum number of electrons in an atom that has: n =3, ml = ±1, ms = + 1/2?
Filling Atomic Orbitals
Fill the atomic orbital diagram for scandium below to answer the following questions.
Filling Atomic Orbitals
Fill the atomic orbital diagram for vanadium below to answer the following questions.
Quantum model: Orbital filling
Draw an atomic orbital diagram for sulfur.
Atom: Electronic configuration
Which of the following orbital diagrams shows a valid ground state electron configuration for an uncharged atom?
Quantum model: Electron configuration
a) What is the full ground state electron configuration (spdf notation) of Al?
b) Draw the energy level diagram for Al.
c) Modify the energy diagram above to show the excited state that required the smallest amount of energy to move the highest energy valence electron to another orbital.
Quantum model: Ground and Excited States
In the energy diagram:
a) Identify all subshells by circling them.
b) Place the name of each subshell next to your circle.
Quantum model: Energy Level Diagram
Consider an atom of the alkali metal Potassium.
a) In the energy diagram given, fill in the required number of electrons for a potassium atom and name the occupied orbitals.
b) The valence electron of potassium can be excited to the next highest energy state in the same valence shell. Below, show how the energy level diagram for the excited atom of potassium has changed. Make sure to name all occupied orbitals.
Orbitals: Lowest energy configuration
Select the orbital diagram of P+ in its lowest energy configuration (ground state).
VSEPR: σ and π Frameworks with Consecutive Double Bonds
Answer the following questions about the species H2CN2, whose Lewis structure is shown below:
Quantum Model: Orbital filling
Which of the following is a correct energy diagram for all the electrons present in a ground state neutral nitrogen atom?
Quantum model: Filling orbitals
Which element has the orbital-filling diagram shown below?
Atom: Electronic configuration
Given the ground-state electronic configuration
[Ar] 4s23d3
1. What is the neutral atom with this electronic configuration?