Beryllium Electron Configuration and Orbital Diagram Model

Beryllium is the 4th element in the periodic table and the symbol is ‘Be’. Beryllium has an atomic number of 4, which means that its atom has four electrons around its nucleus. To write the electron configuration for beryllium, the first two electrons enter the 1s orbital. Since the 1s orbital can hold only two electrons the remaining 2 electrons enter the 2s orbital. Therefore, the electron configuration of beryllium will be 1s² 2s².

The electron configuration of beryllium refers to the arrangement of electrons in the beryllium atom’s orbitals. It describes how electrons are distributed among the various atomic orbitals and energy levels, and provides a detailed map of where each electron is likely to be found.

To understand the mechanism of beryllium electron configuration, you must understand two things. These are orbits and orbitals. Also, you can arrange electrons in those two ways. In this article, I have discussed all the necessary points to understand the mechanism of beryllium electron configuration. I hope this will be helpful in your study.

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Electron arrangement for Beryllium through Bohr Model

The atomic number is the number of electrons in that element. The atomic number of beryllium is 4. That is, the number of electrons in beryllium is 4. Therefore, a beryllium atom will have two electrons in the first shell and two in the 2nd shell. Therefore, the order of the number of electrons in each shell of the beryllium atom is 2, 2.

Electron configuration of beryllium through orbital

Atomic energy shells are subdivided into sub-energy levels. These sub-energy levels are also called orbital. The most probable region of electron rotation around the nucleus is called the orbital.

The sub-energy levels depend on the azimuthal quantum number. It is expressed by ‘l’. The value of ‘l’ is from 0 to (n – 1). The sub-energy levels are known as s, p, d, and f.

Orbit Number	Value of ‘l’	Number of subshells	Number of orbitals	Subshell name	Electrons holding capacity	Electron configuration
1	0	1	1	1s	2	1s2
2	0 1	2	1 3	2s 2p	2 6	2s2 2p6
3	0 1 2	3	1 3 5	3s 3p 3d	2 6 10	3s2 3p6 3d10
4	0 1 2 3	4	1 3 5 7	4s 4p 4d 4f	2 6 10 14	4s2 4p6 4d10 4f14

Explanation:

• If n = 1,
  (n – 1) = (1–1) = 0
  Therefore, the value of ‘l’ is 0. So, the sub-energy level is 1s.
• If n = 2,
  (n – 1) = (2–1) = 1.
  Therefore, the value of ‘l’ is 0, 1. So, the sub-energy levels are 2s, and 2p.
• If n = 3,
  (n – 1) = (3–1) = 2.
  Therefore, the value of ‘l’ is 0, 1, 2. So, the sub-energy levels are 3s, 3p, and 3d.
• If n = 4,
  (n – 1) = (4–1) = 3
  Therefore, the value of ‘l’ is 0, 1, 2, 3. So, the sub-energy levels are 4s, 4p, 4d, and 4f.
• If n = 5,
  (n – 1) = (n – 5) = 4.

Therefore, l = 0,1,2,3,4. The number of sub-shells will be 5 but 4s, 4p, 4d, and 4f in these four subshells it is possible to arrange the electrons of all the elements of the periodic table.

Sub-shell name	Name source	Value of ‘l’	Value of ‘m’ (0 to ± l)	Number of orbital (2l+1)	Electrons holding capacity 2(2l+1)
s	Sharp	0	0	1	2
p	Principal	1	−1, 0, +1	3	6
d	Diffuse	2	−2, −1, 0, +1, +2	5	10
f	Fundamental	3	−3, −2, −1, 0, +1, +2, +3	7	14

The orbital number of the s-subshell is one, three in the p-subshell, five in the d-subshell, and seven in the f-subshell. Each orbital can have a maximum of two electrons.

The sub-energy level ‘s’ can hold a maximum of two electrons, ‘p’ can hold a maximum of six electrons, ‘d’ can hold a maximum of ten electrons, and ‘f’ can hold a maximum of fourteen electrons.

Aufbau is a German word, which means building up. The main proponents of this principle are scientists Niels Bohr and Pauli. The Aufbau method is to do electron configuration through the sub-energy level.

The Aufbau principle is that the electrons present in the atom will first complete the lowest energy orbital and then gradually continue to complete the higher energy orbital.

The energy of an orbital is calculated from the value of the principal quantum number ‘n’ and the azimuthal quantum number ‘l’. The orbital for which the value of (n + l) is lower is the low energy orbital and the electron will enter that orbital first.

Orbital	Orbit (n)	Azimuthal quantum number (l)	Orbital energy (n + l)
3d	3	2	5
4s	4	0	4

Here, the energy of 4s orbital is less than that of 3d. So, the electron will enter the 4s orbital first and enter the 3d orbital when the 4s orbital is full. Following the Aufbau principle, the sequence of entry of electrons into orbitals is 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p.

Therefore, the complete electron configuration for beryllium should be written as 1s² 2s².

Note: The unabbreviated electron configuration of beryllium is [He] 2s². When writing an electron configuration, you have to write serially.

How to draw the orbital diagram of beryllium

The orbital diagram of beryllium is a graphical representation of the electron configuration of beryllium atom. This diagram shows how the electrons in the beryllium atom are arranged in different orbitals and indicates the spin of electrons. Orbital is the region of space around the nucleus of an atom where electrons are found.

To draw an orbital diagram of any atom, you first need to know the atomic orbitals and the orbital notation for that atom, which is already discussed above. Also, you need to know Hund’s and Paul’s exclusion principle. These two fundamental principles explain how these electrons occupy the 1s and 2s orbitals. Below, we define each principle and apply it to beryllium, helping students understand its atomic structure and chemical properties.

Hund’s Rule

Hund’s Rule states that when electrons fill orbitals of the same energy (degenerate orbitals, like the three 2p orbitals), they occupy each orbital singly with parallel spins (e.g., all ↑) before pairing up. This arrangement minimizes electron-electron repulsion and maximizes stability.

Pauli Exclusion Principle

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers. This means each orbital can hold up to two electrons, and they must have opposite spins (e.g., one ↑ and one ↓).

Draw the orbital diagram of beryllium

Orbital diagrams are usually represented by boxes. Each box represents an orbital and the arrows within the box represent the position of the electron. The boxes are arranged in order of energy of the orbitals. The lowest energy orbitals are closest to the nucleus and the higher energy orbitals are progressively further away from the nucleus in order of their energy levels.

To write the orbital diagram of beryllium, 1s is the closest and lowest energy orbital to the nucleus. Therefore, the electrons will first enter the 1s orbital. According to Hund’s principle, the first electron will enter the 1s orbital in the clockwise direction, and the second one will enter the 1s orbital in the anti-clockwise direction. The 1s orbital is now filled with two electrons. Then the next two electrons will enter the 2s orbital just like the 1s orbital. This is clearly shown in the figure of the orbital diagram of beryllium.

Why This Matters for Beryllium

Electron configuration of beryllium in the excited state

Atoms can jump from one orbital to another in an excited state. This is called a quantum jump. The ground-state electron configuration of beryllium is 1s² 2s². When the beryllium atom is excited, then the beryllium atom absorbs energy. As a result, an electron in the 2s orbital jumps to the 2p_x orbital.

The p-subshell has three orbitals. The orbitals are p_x, p_y, and p_z. We already know that each orbital can have a maximum of two electrons. Therefore, the electron configuration of beryllium(Be*) in an excited state will be 1s² 2s¹ 2p_x¹.

The valency of an element is determined by electron configuration in the excited state. Here, beryllium has two unpaired electrons. Therefore, the valency of beryllium is 2.

Electron configuration of Beryllium ion (Be²⁺)

After the electron configuration, the last shell of the beryllium atom has two electrons. Therefore, the valence electrons of beryllium are two. The elements that have 1, 2, or 3 electrons in the last shell donate the electrons in the last shell during bond formation. A beryllium atom donates two electrons of the last shell to turn into a beryllium ion(Be²⁺).

The element that forms a bond by donating electrons is called cation. Beryllium leaves two electrons and turns into a positive ion. Therefore, beryllium is a cation element. 

Be – 2e^– → Be²⁺

Here, the electron configuration of the beryllium ion(Be²⁺) is 1s². This electron configuration shows that the beryllium ion(Be²⁺) acquired the electron configuration of helium and it achieves a stable electron configuration.

Determine the group and period of beryllium through the electron configuration

The last orbit of an element is the period of that element. The electron configuration of the beryllium atom shows that the last orbit of the beryllium atom is 2. So, the period of beryllium is 2.

On the other hand, the number of electrons present in the last orbit of an element is the number of groups in that element. Two electrons exist in the last orbit of the beryllium.

That is, the group number of beryllium is 2. Therefore, we can say that the period of the beryllium element is 2 and the group is 2.

Determine the block of beryllium through the electron configuration

If the last electron enters the s-orbital after the electron configuration of the element, then that element is called the s-block element. The electron configuration of beryllium shows that the last electron of beryllium enters the s-orbital. Therefore, beryllium is the s-block element.

The elements in groups 1 and 2 are the s-block elements. And helium is the s-block element. There are 14 s-block elements in the 118 elements of the periodic table.

The elements of group 2 of the periodic table are alkaline soil metals. The first element of group 2 is beryllium. The element of group 2 is beryllium. Therefore, beryllium is an alkaline soil metal.

Ionic bonds of the beryllium atom

The beryllium atom forms ionic bonds by exchanging electrons with the fluorine atom. BeF₂ is formed by the exchange of electrons between an atom of beryllium and two atoms of fluorine.

The electron configuration shows that there are two electrons in the last orbit of the beryllium atom. The beryllium atom wants to be more stable by forming one helium atom by eliminating two electrons in the last orbit.

Again, seven electrons exist in the last orbit of the fluorine atom. The fluorine atom wants to be more stable like the neon atom by accepting an electron. The beryllium atom donates two electrons of its last orbit to the fluorine atom. Beryllium fluoride(BeF₂) forms compounds through the ionic bond.

Chemical bonding of beryllium

Beryllium oxide

Beryllium reacts with oxygen at high temperatures to produce BeO.

2Be + O₂ → 2BeO

However, BeO is less important due to its low solubility.

BeO + H₂O → Be(OH)₂

BeO reacts with water to produce alkali. However, it destroys the alkalinity of the alkali and the acidity of the acid. BeO reacts with NaOH to form sodium beryllate (Na₂BeO₂).

BeO + 2NaOH → Na₂BeO₂ + H₂O

That is, BeO is both religious oxides. Beryllium is the s-block element of the 2nd group of the periodic table. Beryllium is an exception compared to other elements in the 2nd group of the phase table. The ion of the beryllium atom has a small size and high ionic potential.

The element has a high polarization capacity of cation and the absence of zero d-orbital at the valence level. For this reason, oxides of other elements in the second group are alkaline but BeO exhibits both properties.

Formation of oxygen compounds

Beryllium is the alkaline soil metal of group 2. It reacts very slowly with oxygen as it is electrically positive. And forms oxide compounds.

2Be + O₂ → 2BeO

As the cation size of beryllium increases, the tendency to form peroxide compounds increases.

2BeO + O₂ (500 ° C) → 2BeO₂

Properties of the beryllium atom

• The atomic number of beryllium is 4. The atomic number of an element is the number of electrons in that element. Therefore, the number of electrons in beryllium is four.
• Beryllium’s standard atomic weight is 9.012183.
• Beryllium is an alkaline soil metal.
• The period of the beryllium element is 2 and the group is 2.
• The number of valency and valence electrons of a beryllium atom is two.
• Beryllium is an s-block element.
• Beryllium easily leaves two electrons in its last orbit and turns into a cation. Therefore, beryllium is a very active metal.
• The beryllium atom forms both ionic and covalent bonds.
• The beryllium atom is relatively small and its ionic energy value is relatively high. For this, its electrons cannot be elevated to high energy levels under the influence of flame energy. For this reason, the beryllium element flame test does not show any particular color.
• Ionization energies of beryllium atoms- 1st: 899.5 kJ/mol, 2nd: 1757.1 kJ/mol, 3rd: 14,848.7 kJ/mol
• The oxidation state of the beryllium atom is 2.
• The melting point of a beryllium atom is 1560 K ​(1287 °C, ​2349 °F). And the boiling point is 2742 K ​(2469 °C, ​4476 °F)
• The atomic radius of a beryllium atom is 112 pm.
• The value of electronegativity of a beryllium atom is 1.57.
• The covalent radius of the beryllium atom is 96±3 pm.
• Beryllium atom van der Waals radius 153 pm.
• 2 electrons exist in the last orbit of beryllium.

Reference

1. Zatsarinny, O., Bartschat, K., Fursa, D. V., & Bray, I. (2016). Calculations for electron-impact excitation and ionization of beryllium. Journal of Physics B: Atomic, Molecular and Optical Physics, 49(23), 235701.
2. Uddin, M. A., Haque, A. K. F., Mahbub, M. S., Karim, K. R., Basak, A. K., & Saha, B. C. (2005). Electron impact ionization of beryllium isoelectronic ions. International Journal of Mass Spectrometry, 244(1), 76-83.
3. Vetere, V., Monari, A., Scemama, A., Bendazzoli, G. L., & Evangelisti, S. (2009). A theoretical study of linear beryllium chains: Full configuration interaction. The Journal of chemical physics, 130(2).