Al3+ Electron Configuration

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Orbit Electron Configuration of Aluminium Cation (Al3+) is two electrons in first orbit (K), 8 electrons in second orbit (L).

Orbital Electron Configuration of Aluminium Cation (Al3+) is 1s2 2s2 2p6 which means Al3+ ion have two electrons inside 1s orbital, two electron in 2s orbital and 6 electrons in 2p orbitals.

Also we can replace 1s2 2s2 2p6 with [Ne], therefore electron configuration of Aluminium Cation (Al3+) can also be written as [Ne]

Aluminium atom in total have 13 electrons, to write down the electron configuration of aluminium, the first two electrons would go into the 1s orbital.

Because the 1s orbital can only accommodate two electrons, next two electrons are placed in the 2s orbital, next 6 electrons are placed in 2p orbital.

Out of 3 remaining electrons, 2 would go into 3s orbital and 1 left electron is placed in 3p orbitals. Putting all this together, electron configuration of aluminium is 1s2 2s2 2p6 3s2 3p1. Which can also be written as [Ne] 3s2 3p1 where [Ne] represents electron configuration of noble gas Neon.

Electron Configuration of Aluminium

Orbital Electron Configuration of Aluminium (Al) atom is 1s2 2s2 2p6 3s2 3p1 which means Aluminium atom have two electrons inside 1s orbital, two electron in 2s orbital, 6 electrons in 2p orbitals, 2 electron in 3s orbitals and 1 electron in 3p orbitals.

Read More About Aluminium’s Electron Configuration

Therefore electron configuration of Aluminium atom is 1s2 2s2 2p5 3s2 3p1 but in order to achieve stable electron configuration of nearest noble gas, it easily looses 3 electrons (2 from 3s and 1 from 3p orbitals) and becomes cation which have plus 3 charge on it.

But when an atom of aluminium atom does loose 3 electrons, then number of protons(positive charge) and number of electrons(negative charge) becomes unequal.

Thus forming a Aluminium Ion (Al3+). Which have 3 electron less than aluminium atom.

Al → Al3+ + 3e

Below is atomic composition of Al3+ ion

Aluminium (Al) AtomAluminium (Al3+) Cation
Protons1313
Electrons1310
Neutrons1414
Atomic Weight26.98 u26.98 u

How do you write the electron configuration of Al3+ ion?

Al3+ ion in total have 10 electrons, to write down the electron configuration of this ion, the first two electrons would go into the 1s orbital. Because the 1s orbital can only accommodate two electrons, next two electrons are placed in the 2s orbital, next 6 electrons are placed in 2p orbital. Putting all this together, electron configuration of Al3+ ion is 1s2 2s2 2p6. Which can also be written as [Ne] where [Ne] represents electron configuration of noble gas Neon.

Therefore Electron Configuration of Aluminium (Al3+) ion is 1s2 2s2 2p6. Which is same as electron configuration of noble gas Neon.

Electron Configuration of Aluminium (Al3+) Cation is 1s2 2s2 2p6
Orbital Electron ConfigurationKLMN Electron Configuration
Aluminium (Al3+) Cation1s2 2s2 2p62, 8

2 electrons in K shell
8 electrons in L shell

Setups to figure out Electron Configuration of Al3+ ion

Niels Bohr proposed the idea that electrons revolve around nucleus in specific circular paths called Orbits, but later on Heisenberg found out that it’s impossible to determine position and velocity of an electron inside the atom at same time, so how it’s possible that electrons do circular motion on specific paths in an atom.

In later years, Erwin Schrodinger developed a mathematical formula to compute the probability of finding the location of an electron inside an atom.

On the basis of this probability, the location of an electron inside an atom could be represented as the chances of that electron being located in a certain three-dimensional area surrounding the nucleus.

As 3D region can be explained only using 3 parameters, therefore in order to describe where an electron is? inside the atom.

We need three numbers – Principle Quantum Number (n), Angular Momentum Number (l) and Magnetic Momentum Number (m).

Therefore Orbits(this concept was proposed by Neils Bohr) are further divided into sub-energy levels called subshells. How many subshells an orbit have is equal to Principle Quantum Number (n) of orbit.

Therefore

  • First Orbit (K and n = 1) have 1 subshell
  • Second Orbit (L and n = 2) have 2 subshell
  • Third Orbit (M and n = 3) have 3 subshell
  • Fourth Orbit (N and n = 4) have 4 subshell

These sub-energy levels/subshells have specific regions where probability of finding electrons is maximum. These subshells are names as s, p, d, f and have angular momentum numbers as 0, 1, 2 and 3 respectively.

Which type of subshell an orbit have can be determined using Angular Momentum Number (I).
So
If Principle Quantum Number of an orbit is n
Then subshells in that orbit are 0 to (n – 1)

If
Angular Momentum Number(l) = 0 that means it’s s orbital
Angular Momentum Number(l) = 1 that means it’s p orbital
Angular Momentum Number(l) = 2 that means it’s d orbital
Angular Momentum Number(l) = 3 that means it’s f orbital

First Orbit (K and n = 1)
Angular Momentum Number (l) = 0 to (1 – 1) = 0 (0 to 0)
Which means first orbit just have one subshell which is s

Second Orbit (L and n = 2)
Angular Momentum Number (l) = 0 to (2 – 1) = 1 (0 to 1)
Which means second orbit have two subshells which are s and p

Third Orbit (M and n = 3)
Angular Momentum Number (l) = 0 to (3 – 1) = 2 (0 to 2)
Which means third orbit have three subshells (0, 1, 2) which are s, p and d

Fourth Orbit (N and n = 4)
Angular Momentum Number (l) = 0 to (4 – 1) = 3 (0 to 3)
Which means fourth orbit have four subshells (0, 1, 2, 3) which are s, p, d and f

OrbitPrinciple Quantum NumberNumber of SubshellsSubshells
First Orbit (K)n = 111s
Second Orbit (L)n = 222s
2p
Third Orbit (M)n = 333s
3p
3d
Fourth Orbit (N)n = 444s
4p
4d
4f

These s, p, d and f subshells further have subregions which are called Orbitals, orbitals are just regions inside a subshell where probability of existence of an electron is quite high.

How many orbitals a subshell have depends upon it’s Angular Momentum Number (l) and can be calculated using formula.
Number of orbitals in a subshell = 2l + 1 where I is Angular Momentum Number of a subshell.

Therefore
s subshell (Angular Momentum Number l = 0)
Number of orbitals = 2(0) + 1 = 1
So s subshell just have one orbital

p subshell (Angular Momentum Number l = 1)
Number of orbitals = 2(1) + 1 = 3
So p subshell have three orbitals

d subshell (Angular Momentum Number l = 2)
Number of orbitals = 2(2) + 1 = 4 + 1 = 5
so d subshell have five orbitals

f subshell (Angular Momentum Number l = 3)
Number of orbitals = 2(3) + 1 = 6 + 1 = 7
so f subshell have seven orbitals

Moreover electron holding capacity of a subshell can be calculated using formula
Number of electrons which a subshell can hold = 2(2I + 1) where I is Angular Momentum Number of subshell

Therefore
s subshell (Angular Momentum Number l = 0)
Number of electrons it can hold = 2(2(0) + 1) = 2(1) = 2
So s subshell can hold maximum two electrons

p subshell (Angular Momentum Number l = 1)
Number of electrons it can hold = 2(2(1) + 1) = 2(3) = 6
So p subshell can hold maximum six electrons

d subshell (Angular Momentum Number l = 2)
Number of electrons it can hold = 2(2(2) + 1) = 2(4 + 1) = 2(5) = 10
so d subshell can hold maximum ten electrons

f subshell (Angular Momentum Number l = 3)
Number of electrons it can hold = 2(2(3) + 1) = 2(6 + 1) = 2(7) = 14
so f subshell can hold maximum fourteen electrons

SubshellAngular Momentum Number (I)Number of Orbitals in
Subshell (2l + 1)
Maximum Electrons Subshell can hold 2(2l + 1)
s012
p136
d2510
f3714

Summarising all this we can write energy levels in an atom as

1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f 5g

But next question which arises is “in which order these orbitals should be filled in to figure out electron configuration of an atom?”.

Like should 2 electrons be filled in 1s orbital first or 3p orbital first???

Well answer to this question is Aufbau Principle.

According to the Aufbau Principle, in the ground state of an ion or an atom, electrons first occupy the atomic orbitals of lowest energy levels before filling up in higher energy levels. What this indicates is that the orbital with the lower energy will be filled first, followed by the orbital with the greater energy.

As per this principle energy of any orbital depends upon sum of Principle Quantum Number (n) and Angular Quantum Number (l).
Therefore
Energy of Orbital = n + l

So lower the value of n + l is lower its energy.

OrbitalnIEnergy (n + l)
1s101
2s202
2p213
3s303
3p314
3d326
4s404
4p415
4d426
4f437

From the above table its clear that 4s have less energy than 3d, so it should be filled first.
Based upon the energies of orbitals as per Aufbau Principle, order of filling of orbitals is 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p 8s and so on.

It’s tricky to remember what’s order of filling of orbitals as per Aufbau Principle, so you can use below diagram for easily filling up orbitals. Just follow the arrows from top right corner to bottom left corner diagonally.

Order of filling orbitals in an atom as per Aufbau Principle
Aufbau Principle Filling Of Orbitals Order

Order of filling of orbitals as per Aufbau Principle is 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p 8s and so on.

As Al3+ cation have 12 electrons, therefore it’s electron configuration is 1s2 2s2 2p6. Which means Al3+ cation have 2 electrons each in its 1s, 2s orbitals and 6 electrons in 2p orbitals.

Does Aluminium (Al3+) ion have stable electron configuration?

Electron configuration of aluminium ion (Al3+) is 1s2 2s2 2p6 which is same as electron configuration of Neon Noble Gas. Therefore Aluminium (Al3+) ion have stable electron configuration.

How many electron shells does Al3+ ion have?

Al3+ ion have orbital electron configuration 1s2 2s2 2p6 which in terms of KLMN shells can be written as 2, 8
This means that Al3+ ion have 2 electrons in K shell and 8 electrons in L shell.
Therefore Al3+ ion have 2 electron shells.

Shell of Al3+ IonNumber of electrons
K shell2
L shell8
M shell0
N shell0

As another name for shells is energy levels, because shells just represent different energy states of electrons in an atom, therefore in total Al3+ have 2 energy levels which are K and L.

How many orbitals are in Al3+ ion?

Electron Configuration of Al3+ ion is 1s2 2s2 2p6 which means
Al3+ ion have
– 2 electrons in 1s subshell
– 2 electrons in 2s subshell
– 6 electrons in 2p subshell

Orbital Diagram of distribution of electrons in Al3+ ion

1s subshell have just one orbital
2s subshell also just have one orbital
2p subshell have 3 orbitals

So in total Al3+ ion 1 + 1 + 3 = 5 orbitals

Therefore Al3+ ion have in total 5 orbitals.

From the above diagram showing distribution of electrons in orbitals of Al3+ ion, it’s clear that in total all of its 6 orbitals are fully filled (these are 1s, 2s, 2p orbitals)

Does Al3+ have unpaired electrons?

Electron Configuration of Al3+ ion is 1s2 2s2 2p6 which means
Al3+ ion have
– 2 electrons in 1s subshell
– 2 electrons in 2s subshell
– 6 electrons in 2p subshell

Orbital Diagram of distribution of electrons in Al3+ ion

From the above diagram it can be clearly observed that all of orbitals 1s, 2s and 2p are fully filled and there’s no orbital having single electron. Therefore Al3+ ion doesn’t have any unpaired electron.

As Al3+ don’t have any unpaired electrons therefore its Diamagnetic.

Does Al3+ have d orbitals?

Electron Configuration of Al3+ ion is 1s2 2s2 2p6 
Therefore Al3+ ion just have electrons in s, p orbitals and doesn’t have any d orbitals.

How many Valence Electrons does Al3+ have?

Number of electrons in the last orbit are called valence electrons.

Electron Configuration of Al3+ ion is 1s2 2s2 2p6  therefore its last orbit is 2 (L shell) as last orbit of Al3+ ion have 8 electrons (2 in 2s and 6 in 2p orbitals) therefore number of valence electrons in Al3+ ion is 8.

As Valence Shell of Al3+ ion is L shell and its fully filled with 8 electrons therefore Al3+ ion have a filled valence shell.

Valence Electrons
Aluminium (Al) Atom3
(2 in 3s and 1 in 3p)
Al3+ ion8
(2 in 2s and 6 in 2p)

So Al3+ ion have 8 valence electrons while Aluminium (Al) atom have just 3.

Does Al3+ have octet?

Electron Configuration of Al3+ ion is 1s2 2s2 2p6 which in terms of KLMN shells can be written as 2, 8
2 electrons in K shell
8 electrons in L shell

Octet means having 8 electrons in outermost shell.
As Al3+ ion have 8 electrons in its outermost shell (L) therefore it have an octet.

Differences between Aluminium (Al) atom and Al3+ cation (Table)

Aluminium (Al) AtomAl3+ Cation
Electrons1310
Electron Configuration1s2 2s2 2p6 3s2 3p11s2 2s2 2p6
KLMN Electron Configuration2, 8, 32, 8
Unpaired Electrons1
(Unpaired electron in 3p orbital)
0
Outermost ShellM shellL shell
Atomic Species TypeAtomCation
State of Electron ConfigurationNot stable
Want to loose 3 electrons
Stable Neon Noble Gas
Electron Configuration
Radius184 picometer53 picometer
Magnetic BehaviourParamagneticDiamagnetic
Electrostatic ForceDoes not attract anionsDoes attract anions and
form ionic bonds with them
ExistenceUsually exist as a solidIs only found in solutions

Summary

  • Aluminium Ion (Al3+) is formed when an aluminium atom looses 3 electrons
  • Electron Configuration of Aluminium Ion (Al3+) is 1s2 2s2 2p6
  • KLMN Electron Configuration of Aluminium Ion (Al3+) is 2, 8 which means 2 electrons in K shell and 8 in L shell
  • Electron Configuration of Aluminium Ion (Al3+) is same as that of Neon Noble Gas
  • Aluminium Ion (Al3+) have 2 electron shells which are K and L
  • In total Aluminium Ion (Al3+) have five orbitals
  • Aluminium Ion (Al3+) don’t have any unpaired electron
  • Aluminium Ion (Al3+) have 8 valence electrons
  • Aluminium Ion (Al3+) have an octet
  • Aluminium Ion (Al3+) is smaller in radius as compared to Aluminium atom
  • Aluminium Ion (Al3+) is Diamagnetic
  • Aluminium Ion (Al3+) is usually found in solutions
  • Aluminium Ion (Al3+) forms ionic compounds

FAQs

What is electron configuration of Aluminium (Al3+) ion?

When an atom of aluminium loose 3 electrons, then number of protons(positive charge) and number of electrons(negative charge) becomes unequal. Thus forming an Aluminium Ion (Al3+).

As electron configuration of Aluminium atom is 1s2 2s2 2p6 3s2 3p1 and formation of aluminium ion (Al3+) require loosing of 3 electrons therefore electron configuration of aluminium ion is 1s2 2s2 2p6.

What is KLMN electron configuration of Aluminium (Al3+) ion?

KLMN electron configuration of Aluminium (Al3+) ion is 2, 8 which means it have 2 electrons in K shell and 8 electrons in L shell.

Does Aluminium (Al3+) ion have stable electron configuration?

Electron configuration of aluminium ion (Al3+) is 1s2 2s2 2p6 which is same as electron configuration of Neon Noble Gas. Therefore Aluminium (Al3+) ion have stable electron configuration.

In what type of orbital is the outermost electron in Al3+ ion?

Electron configuration of aluminium ion (Al3+) is 1s2 2s2 2p6
From this it can be clearly observed that outermost electron in aluminium ion (Al3+) is present in 2p orbital.

Which atomic species have electron configuration 1s2 2s2 2p6?

Aluminium Ion (Al3+)

How many unpaired electrons are there in Aluminium (Al3+) ion?

Electron configuration of aluminium ion (Al3+) is 1s2 2s2 2p6
For this it can be clearly observed that all of orbitals are fully filled and there’s not even single orbital which just have one electron. Therefore number of unpaired electrons in aluminium ion (Al3+) is zero.

How many valence electrons does Aluminium (Al3+) ion?

Number of electrons in the last orbit are called valence electrons.

Electron Configuration of Al3+ ion is 1s2 2s2 2p6  therefore its last orbit is 2 (L shell) as last orbit of Al3+ ion have 8 electrons (2 in 2s and 6 in 2p orbitals) therefore number of valence electrons in Al3+ ion is 8.

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