Boron (B) Orbital diagram, Electron configuration, and Valence electrons

The electron configuration of Boron can be found using the Aufbau principle.

Aufbau Principle:

• The word ‘Aufbau’ in German means ‘building up’.
• The Aufbau rule simply gives the order of electrons filling in the orbital of an atom in its ground state.
• It states that orbital with the lowest energy level will be filled first before those with high energy levels. In short, the electrons will be filled in the orbital in order of their increasing energies.
• For example, the 1s orbital will be filled first with electrons before the 2s orbital.

Simply understand that there are commonly four different types of subshells – s, p, d, and, f.

These subshells can hold a maximum number of electrons on the basis of a formula, 2(2l + 1) where ‘l’ is the azimuthal quantum number.

Value of ‘l’ for different subshells.

Subshells	Value of ‘l’	Maximum number of electrons, 2(2l + 1)	Number of orbitals in the subshell
s	0	2	1
p	1	6	3
d	2	10	5
f	3	14	7

So, in short, the s subshell can hold a maximum of 2 electrons(1 orbital), the p subshell can hold 6 electrons(3 orbitals), the d subshell can hold 10 electrons(5 orbitals), and the f subshell can hold at most 14 electrons(7 orbitals).

Now, the electron configuration of an atom can be built by filling the electrons in a lower energy subshell first then higher, higher, and higher.

Generally, (n + l) rule is used to predict the energy level of subshells.

n = principle quantum number

l = Azimuthal quantum number

⇒ Lower the value of (n + l) for an subshell, the lower its energy, hence, it will be filled first with electrons.

⇒ For two different subshells having same (n + l) value, then the subshell with lower value of n has lower energy.

So, all these are basics of How filling of electrons will be done in different subshells, obviously, you don’t have so much time for writing electron configuration by using so many rules.

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

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.

Boron Electron configuration using the Aufbau Principle

• A Boron atom is a neutral atom that has 5 atomic numbers which implies it has a total of 5 electrons.
• As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
• Now, for the electron configuration of Boron, the first 2 electrons will go in 1s orbital since s subshell can hold a maximum of 2 electrons.
• The next two electrons will go in the 2s orbital, after that, we are left with only 1 electron, which will go in the 2p orbital.
• Therefore, the electron configuration of Boron will be 1s²2s²2p¹.

Boron (B) Electron Configuration

Check – Electron configuration calculator to count the electron configuration for any atom

Orbital diagram for Boron

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 drawing the orbital diagram for an atom.

(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 (↓)”.

If you understand the above rules then constructing the orbital diagram or orbital notation for Boron 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 also be filled with the same order as described by the Aufbau principle. (1s < 2s < 2p < 3s……and so on.)

Also check –

• Orbital diagram calculator
• Orbital diagram for all elements in the periodic table

What is the Orbital diagram for Boron?

We know the electron configuration of Boron is 1s²2s²2p¹, now for drawing its orbital diagram, we need to show its electrons in form of an arrow in different boxes using Hund’s and Pauli exclusion rule.

• The orbital diagram of Boron contains 1s orbital, 2s orbital, and 2p orbital. 1s orbital contains 1 box, 2s orbital also contains 1 box and 2p orbital contains 3 boxes.
• Boron has a total of 5 electrons and one box can hold up to the two electrons.
• Therefore, the first two electrons will go in the 1s orbital, and the next two will go in the 2s orbital, now we are left with only 1 electron.
• This remaining 1 electron will go in a 2p orbital.

Boron Orbital diagram

Electron configuration Vs Orbital diagram for Boron

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).

Also Read:–

• How to write the Electron configuration for any elements?
• How to draw the Orbital diagram for an atom?

Electron configuration for Boron via Bohr model (Orbit)

Bohr model describes the visual representation of orbiting electrons around the small nucleus. It used different electron shells such as K, L, M, N…so on.

These electron shells hold a specific number of electrons that can be calculated via the 2n² formula where n represents the shell number.

Electron shells	Shell number (n)	Max. number of electrons (2n2)
K	1	2
L	2	8
M	3	18
N	4	32

So, K is the first shell or orbit that can hold up to 2 electrons, L is the 2nd shell which can hold up to 8 electrons, M is the third shell that can hold up to 18 electrons, and N is the fourth shell that can hold up to 32 electrons.

Now, Boron has an atomic number of 5 and it contains a total number of 5 electrons. Hence, 2 electrons will go in the first shell(K) and 3 electrons will go in the second shell(L).

Therefore, the electrons per shell for Boron is 2, 3, hence, we can say, based on the shell, the electronic configuration of the Boron atom is [2, 3].

Also check – How to draw Bohr model of Boron atom

Boron Valence electrons

Valence electrons are the outermost electrons present in the outermost shell of an atom. They have more energy, hence, they are part of most chemical reactions.

We can find valence electrons of an atom either by knowing its periodic group number or its electron configuration. Both these ways are super easy.

Finding Boron Valence electrons through the Group number

For neutral atoms, the valence electrons of an atom will be equal to its main periodic group number. However, for transition metals, the process of finding valence electrons is complicated.

Now, for determining the valence electron for the Boron atom, look at the periodic table and find its Group number. The group number can be found from its column on the periodic table.

So, the number of valence electrons in Boron is 3. Since it belongs to Group 13 (also called 3A) in the Periodic table.

Finding Boron Valence electrons through the Electron configuration or Bohr model

We know, the electron configuration of the Boron atom is 1s²2s²2p¹, and valence electrons are those electrons found in the outer shell of an atom.

This electron configuration of Boron shows that the outer shell of Boron has 3 electrons(2s²2p¹), hence, the number of valence electrons in the Boron atom is 3.

Also, we know, that the electron configuration of Boron-based on the shells is [2, 3], which means, that two electrons are present in the first shell, and three electrons are present in 2nd shell or outer shell.

Hence, the electrons found in the 2nd shell of the Boron atom are its valence electrons because it is the outermost shell also called the valence shell.

The 2nd shell or outer shell of the Boron atom contains 3 electrons, therefore, the number of valence electrons in the Boron atom is 3.

Check – Valence electron calculator to calculate the number of valence electrons for any atom

Electron configuration, Valence electrons, and Orbital diagram of Boron in tabular form

Name of atom	Boron (B)
Number of electrons	5
Number of electrons per shell	[2, 3]
Number of valence electrons	3
Electron configuration	1s22s22p1 or [He] 2s22p1
Orbital diagram	Consists of three orbitals – 1s, 2s, and, 2p

Also Read:

• Nitrogen orbital diagram and electron configuration
• Oxygen orbital diagram and electron configuration
• Carbon orbital diagram and electron configuration
• Fluorine orbital diagram and electron configuration
• Neon orbital diagram and electron configuration
• Sodium orbital diagram and electron configuration
• Magnesium orbital diagram and electron configuration
• Aluminum orbital diagram and electron configuration
• Silicon orbital diagram and electron configuration
• Phosphorous orbital diagram and electron configuration
• Sulfur orbital diagram and electron configuration
• Chlorine orbital diagram and electron configuration
• Argon orbital diagram and electron configuration
• Potassium orbital diagram and electron configuration
• Calcium orbital diagram and electron configuration
• Beryllium orbital diagram and electron configuration
• Lithium orbital diagram and electron configuration

FAQ

What are the Ground state and Excited-state Electron configurations of Boron? There is a simple difference between Ground state and Excited-state configuration. The ground state configuration of an atom is the same as its regular electron configuration in which electrons remain in the lowest possible energy. So, the ground-state electron configuration for the Boron atom is 1s22s22p1. The excited-state configuration of an atom is different from the regular configuration of an atom, this occurs, when an electron is excited and jumps into a higher orbital. The excited-state electron configuration for Boron is 1s22s12p2.

What is the shorthand electron configuration of Boron? The shorthand electron configuration for Boron atom is [He] 2s22p1. ∴ [He] electron configuration is 1s2.

Which element has the 1s22s22p1 Electron configuration? Element with electron configuration 1s22s22p2 is Boron (B) which has the atomic number of 5.

How many valence electrons does Boron have? The boron atom has 3 valence electrons in its outermost or valence shell. Boron is belonged to group 13th and has the atomic number of 5.

What is the orbital diagram for Boron (B)? The orbital diagram for Boron is drawn with 3 orbitals. The orbitals are 1s, 2s, and 2p. The Boron orbital diagram contains 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, and the remaining one electron in the 2p orbital. The orbital diagram for a ground-state electron configuration of Boron atom is as follow –

What is the electron configuration of the B3+ ion? We know, in general, that the electron configuration of Boron (B) is 1s22s22p1. Now, in the B3+ ion, the positive charge means, Boron loses three electrons.  Therefore, to write the electron configuration of the B3+ ion, we have to remove three electrons from the configuration of Boron (B). ∴ The resulting electron configuration for the Boron ion (B3+) will be 1s2. It resembles the configuration of the nearest inert gas i.e Helium.

Properties and Uses of Boron

• In amorphous form, it appears as a brown powder and in crystalline form, it appears as a brittle, dark metalloid.
• It belongs to Group 13 and period 2 in the periodic table.
• It has three valence electrons that are used to form a covalent bond.
• It has a boiling point of 3927 °C and a melting point of 2076 °C.
• It has a rhombohedral crystal structure.
• Its oxidation state varies from -5 to +3.
• Boron is used to increase the surface hardness of steels and alloys.
• It is used in the Detergent formulation and bleaching agents.
• It is also used in semiconductors and magnets.
• It is used in various pharmaceutical and biological applications.

Reactions for Boron

When boron undergoes halogenation, it gives trihalides

⇒ 2B + 3Br₂ → 2BBr₃

When boron reacts with air, at a very high temperature, it burns and forms boron trioxide.

⇒ 4B + 3O₂ → 2B₂O₃

Summary

• The electron configuration of Boron in terms of the shell or orbit is [2, 3].
• The ground-state electron configuration of the Boron (B) atom is 1s²2s²2p¹. And for the excited state, it is 1s²2s¹2p².
• The shorthand electron configuration for Boron is [He] 2s²2p¹.
• The electron configuration for the B³⁺ is 1s².
• The number of valence electrons available for Boron atoms is 3. Boron is situated in Group 13th and has an atomic number of 5.
• The first shell of Boron has 2 electrons and the outer shell or valence shell of Boron has 3 electrons, hence, the number of valence electrons in the Boron atom is 3.
• The orbital diagram for Boron is drawn by following three principles – the Aufbau principle, Hund’s principle, and Pauli’s exclusion principle.
• The Boron orbital diagram comprises three orbitals. The three orbitals are 1s, 2s, and 2p.
• The first two electrons will go in the 1s orbital, the next two in the 2s orbital, and the remaining one in the 2p orbital.