Orbital diagrams, How to draw with examples?

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What is orbital diagram and how to draw it?

What is the Orbital diagram?

  • “Orbital diagrams are pictorial descriptions of the electrons in an atom. Three rules are useful in forming orbital diagrams.
  • According to the Auf Bau Principle, each electron occupies the lowest energy orbital.
  • The Pauli Exclusion Principle says that only two electrons can fit into a single orbital.”

Source: brightstorm.com

In this article, we will discuss – How to draw an Orbital diagram or an Orbital notation configuration?

How to Draw Orbital Diagrams?

The orbital diagram simply represents the arrangement of electrons in the different orbitals of an atom, it uses an arrow to represent the electrons, every orbital(one box) contains a maximum of 2 electrons.

There are three rules followed for constructing the orbital diagram. The three rules are – (a). Aufbau’s rule (b). Hund’s rule (c). Pauli Exclusion rule.

(1). Aufbau’s principle:- This rule state that the lower energy orbital will be filled before the higher energy orbital, for example – the 1s orbital will fill before the 2s orbital.

(2). Hund’s rule:- This rule state that each orbital of a given subshell should be filled with one electron each before pairing them. That means “Each orbital gets one electron first, before adding the second electron to the orbital”.

(3). Pauli Exclusion Principle:- This rule state that, no two electrons can occupy the same orbital with the same spin. That means “One must be spin up (↑) and one must be spin down (↓)”.

Orbital diagram rules and examples

If you understand the above rules then constructing the orbital diagram or orbital notation for any atom is super easy.

Basics of Orbital diagram:-

There are different types of orbitals – s, p, d, and, f. These orbitals contain a number of boxes that can hold a number of electrons. Let’s see.

Each box will hold a maximum of 2 electrons with opposite spin.

  • S orbital contains 1 box that can hold a maximum of 2 electrons.
  • P orbital contains 3 boxes that can hold a maximum of 6 electrons.
  • D orbital contains 5 boxes that can hold a maximum of 10 electrons.
  • F orbital contains 7 boxes that can hold a maximum of 14 electrons.

The orbital diagram will be filled in the same order as described by the Aufbau principle.

“The Aufbau principle states that electrons will inhabit the lowest-energy orbitals first. This means that electrons can only enter higher-energy orbitals after lower-energy orbitals have been entirely filled.”

Aufbau rule for constructing orbital boxes diagram

We have a diagonal rule for electron filling order in the different subshells using the Aufbau principle.

Aufbau principle for Orbital diagram

So, the order in which the orbitals are filled with electrons from lower energy to higher energy is –

 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s < 5f < 6d < 7p and so on.

Trick:- you can learn the order of the orbital box diagram and then fill out the electrons in it.

orbital filling diagram or box diagram

How to draw an Orbital diagram/notation?

To draw the orbital diagram for an atom, follow these basic steps.

  1. Find the number of electrons in an atom.
  2. Write the electron configuration for an atom to determine which orbitals should be filled.
  3. Fill the electrons in empty boxes using three principles – Aufbau, Hund’s, and Pauli Exclusion.

Let’s take an example of the Nitrogen atom to understand the concept of the making of filling the orbital diagram.

How to draw an Orbital diagram for Nitrogen?

We know that the nitrogen atom has a total of 7 electrons that need to be placed into orbitals, now for drawing its orbital diagram, we need to show its electrons in form of an arrow in different boxes using Aufbau, Hund’s, and Pauli’s exclusion rule.

  • Nitrogen has a total of 7 electrons and its electron configuration is 1s22s22p3.
  • As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
  • 1s orbital contains 1 box, 2s orbital also contains 1 box and 2p orbital contains 3 boxes. Also, one box can hold up to two electrons.
  • Therefore, the first two electrons of nitrogen will go in the 1s orbital, and the next two will go in the 2s orbital, now we are left with 3 electrons.
  • These 3 electrons will go in the 2p orbital, since, the 2p orbital has 3 boxes, so, these electrons will be filled using Hund’s rule. (Each box gets one electron first).

How to draw orbital diagram for Nitrogen

Also checkOrbital diagram calculator

Let’s take one more example to understand the procedure of drawing the orbital diagram for an atom.

How to draw an Orbital diagram for Potassium?

We know the potassium has a total of 19 electrons that need to be placed into orbitals, now for drawing its orbital diagram, we need to show its electrons in form of an arrow in different boxes using Aufbau, Hund’s, and Pauli’s exclusion rule.

  • Potassium has a total of 19 electrons and its electron configuration is 1s22s22p63s23p64s1.
  • As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
  • 1s orbital contains 1 box, 2s orbital also contains 1 box, 2p orbital contains 3 boxes, 3s orbital contains 1 box, 3p orbital contains 3 boxes, and 4s orbital contains 1 box.  Also, one box can hold up to two electrons.
  • Therefore, the first two electrons of potassium will go into the 1s orbital, the next two will go into the 2s orbital, and after that, the next six electrons will go into the 2p orbital, since, the 2p orbital has 3 boxes.
  • After that, the next two electrons will go in the 3s orbital, and the next six electrons will enter the 3p orbital. Now, the 3p orbital is full.
  • Therefore, the remaining one electron will go in 4s orbital in the clockwise direction. (↑)

How to draw orbital notation for Potassium

Take one more example of the atom – Chlorine (Atomic no. 17).

How to draw an Orbital diagram for Chlorine?

  • Chlorine has a total of 17 electrons and it’s electron configuration is 1s22s22p63s23p5.
  • As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
  • 1s orbital contains 1 box, 2s orbital also contains 1 box, 2p orbital contains 3 boxes, 3s orbital contains 1 box and 3p orbital contains 3 boxes.
  • Therefore, the first two electrons of chlorine will go into the 1s orbital, the next two will go into the 2s orbital, and after that, the next six electrons will go into the 2p orbital, since, the 2p orbital has 3 boxes.
  • After that, the next two electrons will go into the 3s orbital, and the remaining five electrons will enter the 3p orbital, since, the 3p orbital has 3 boxes, so, these electrons will be filled using Hund’s rule. (Each box gets one electron first, then start pairing).

How to do Orbital diagram for Chlorine

At last, Let’s try to construct one more orbital diagram for atom – Sodium (Atomic no. 11).

How to draw an Orbital diagram for Sodium?

  • Sodium has a total of 11 electrons and its electron configuration is 1s22s22p63s1.
  • As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
  • 1s orbital contains 1 box, 2s orbital also contains 1 box, 2p orbital contains 3 boxes, and 3s orbital contains 1 box.
  • Therefore, the first two electrons of the Sodium atom will go into the 1s orbital, the next two will go into the 2s orbital, after that, the next six electrons will go into the 2p orbital, since, the 2p orbital has 3 boxes, so, these electrons will be filled using Hund’s rule. (Each box gets one electron first, then start pairing).
  • After filling these orbitals, we are still left with 1 electron, this will go in 3s orbital.

How to draw Orbital box diagram for Sodium

Atomic numberName of the ElementsOrbital diagram
1Hydrogen orbital diagramConsists of one orbital – 1s.
2Helium orbital diagramConsists of one orbital – 1s.
3Lithium orbital diagramConsists of two orbitals – 1s and 2s.
4Beryllium orbital diagramConsists of two orbitals – 1s and 2s.
5Boron orbital diagramConsists of three orbitals – 1s, 2s, and, 2p
6Carbon orbital diagramConsists of three orbitals – 1s, 2s, and, 2p
7Nitrogen orbital diagramConsists of three orbitals – 1s, 2s, and, 2p
8Oxygen orbital diagramConsists of three orbitals – 1s, 2s, and, 2p
9Fluorine orbital diagramConsist of three orbitals – 1s, 2s, and, 2p
10Neon orbital diagramConsists of three orbitals – 1s, 2s, and, 2p
11Sodium orbital diagramConsists of four orbitals – 1s, 2s, 2p, and, 3s.
12Magnesium orbital diagramConsists of four orbitals – 1s, 2s, 2p, and, 3s.
13Aluminum orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
14Silicon orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
15Phosphorus orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
16Sulfur orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
17Chlorine orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
18Argon orbital diagramConsists of five orbitals – 1s, 2s, 2p, 3s, and 3p.
19Potassium orbital diagramConsists of six orbitals – 1s, 2s, 2p, 3s, 3p, and 4s.
20Calcium orbital diagramConsists of six orbitals – 1s, 2s, 2p, 3s, 3p, and 4s.

What is the difference between an Electron configuration or an Orbital diagram?

The main difference between the orbital diagram and electron configuration is an orbital diagram shows electrons in form of arrows whereas an electron configuration shows electrons in form of numbers. Also, the orbital diagram shows details on the spin of electrons whereas the electron configuration doesn’t show it.

Both these follow the Aufbau principle (Diagonal rule).

Take a look at the Electron configuration vs Orbital diagram for Nitrogen.

Electron configuration vs Orbital diagram

Please read out the articles on the Orbital diagram and electron configuration for various atoms to understand the concept better.

Also Read:-

FAQ

What are the 3 rules for orbital diagrams?

The 3 rules for drawing the orbital diagrams are – the Aufbau Principle rule, the Pauli-Exclusion Principle, and Hund’s rule.

How do you write orbital diagrams?

We can write an orbital diagram for any atom by following three basic steps-

  1. Find the number of electrons in an atom.
  2. Write the electron configuration for an atom to determine which orbitals should be filled.
  3. Fill the electrons in empty boxes using three principles – Aufbau, Hund’s, and Pauli Exclusion rules.

What are the 4 types of orbital?

There are 4 types of orbital – s, p, d, and f.

  • S orbital contains 1 box.
  • P orbital contains 3 boxes.
  • D orbital contains 5 boxes.
  • F orbital contains 7 boxes.

What do orbital diagrams show?

Orbital diagrams show the arrangement of electrons in the different orbitals of an atom, it uses an arrow to represent the electrons.

How do you draw an Orbital diagram?

The orbital diagrams are drawn by following three basic rules – the Aufbau Principle rule, the Pauli-Exclusion Principle, and Hund’s rule. There are different types of orbitals – s, p, d, and, f. These orbitals contain a number of boxes that can hold a number of electrons.

How Electron is represented in the Orbital diagram?

The electron is shown in form of arrows in the orbital box diagram.

  • An upward direction arrow(↑) represents a spin-up electron, and we always start orbital boxes with a spin-up arrow.
  • A downward direction arrow(↓) represents a spin-down electron.
  • When the orbital is filled with spin-up and spin-down electrons, it is said to be electron paired(↑↓).

How unpaired electrons are represented in the Orbital box diagram?

When the orbital box contains only one electron, it is said to be an unpaired electron box. The unpaired electron is always represented with spin-up arrows (↑), it doesn’t contain a spin-down arrow(↓).

What is the order of filling electrons in the Orbital boxes diagram?

The orbital diagram will be filled in the same order as described by the Aufbau principle.

The order in which the orbitals are filled with electrons from lower energy to higher energy is –

1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s < 5f < 6d < 7p and so on.

The above order means –

  • 1s orbital will be filled first than 2s.
  • Same as 2s orbital will be filled first than 2p orbital…..and so on.

Summary

  • The orbital diagram is drawn by using three rules – Aufbau’s rule, Hund’s rule, and Pauli’s exclusion rule.
  • For drawing the orbital diagram or orbital notation, first, find the number of electrons in an atom then write its electron configuration to determine which orbital should be filled.
  • And then fill the electrons in empty orbital boxes using three rules.
  • The electron is always filled in an orbital box starting with a spin-up arrow(↑).
  • Orbital configuration represents electrons in form of the arrow(↑↓) and Electron configuration represents electrons in form of numbers.
  • One box of orbital diagrams can hold up to 2 electrons.
  • Both the Orbital configuration and Electron configuration follow the Aufbau principle. That means the lower energy orbital will be filled first(i.e. 1s orbital is filled before the 2s orbital).

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