SO2 Valence Electrons

SO2 valence electrons are 18. Sulfur and oxygen are both members of the group VIA element series. As a result, their valence shell contains six electrons. To get the number of valence electrons in a molecule, multiply the number of valence electrons in each element by the number of atoms in the molecule.

so2 valence electrons

What is Sulfur Dioxide (SO2)?

Sulfur Dioxide, alternatively referred to as Sulphur Dioxide, is the product of a connection between sulfur and oxygen atoms. It is denoted by the formula SO2. We shall discuss the molecular geometry of SO2, the electron geometry of SO2, the bond angle of SO2, and the Lewis structure of SO2.

One sulfur atom and two oxygen atoms make up the sulfur dioxide molecule. By following the laws of VSEPR theory and taking into account the stability of intermediate structures, we shall design the Lewis structure of the SO2 molecule. We can estimate the hybridization of atoms after getting the Lewis structure of SO2.

Sulfur dioxide is an odorless inorganic gas that is also very poisonous. When dissolved in water, it produces a weak acid solution. This gas is created when petroleum fuel is burned in cars and industrial plants.

Molecule Name Sulfur Dioxide
Bond Angles 119 degrees
Molecular Geometry Trigonal Planar
Hybridization Sp2 hybridization
Valence Electrons 18

Lewis Structure of SO2

In the SO molecule, there are two double bonds formed between the sulfur atom and the oxygen atom. In addition, the sulfur atom has a lone pair, and each oxygen atom contains two lone pairs in the SO2 Lewis structure.

The Lewis structure of SO2 is drawn using the procedures outlined below. The following sections go into further depth about each phase. If you are a newbie to the lewis structure drawing, take your time and go through each part carefully to ensure that you grasp everything.

Take a look at the illustrations to ensure that you understand each step.

so2 molecule

Number of Electrons in Ethene’s Valance Shells

Sulfur and oxygen are both elements that belong to the group VIA element series. As a result, they have six electrons in the valence shell of their atom. To calculate the number of valence electrons in a molecule, the valence electrons of each element should be multiplied by the number of atoms in the molecule that element has.

The total number of valence electrons provided by two oxygen atoms is 6 * 2 = 12 electrons.

The total number of valence electrons provided by the sulfur atom is 6 * 1 = 6.

The SO2 molecule does not contain any charges. As a result, there is no addition or decrease of valence electrons as a result of charges.

Total valence electrons = 12 + 6 = 18

Total number of Valence Electron

Total valance electrons pairs= σ bonds + π bonds + lone pairs at valence shells

The total number of electron pairs is calculated by dividing the total number of valence electrons by two. In the case of the SO2 molecule, the total number of electron pairs is nine.

Central Atom of the Ethene Molecule

There are various prerequisites to fulfill to be the central atom. One of the most important requirements for becoming a center atom is to have a high valence. Sulfur has the greatest valence of any element in the SO2 molecule, surpassing both oxygen and nitrogen.

Atoms with Lone Pairs

Following the completion of the sketch, we should begin marking lone pairs on the atoms. There are two bonds shown in the sketched drawing between and among atoms

  • There are currently two S-O bonds in existence. To draw the remainder of the structure (as shown by the lone electrons), there are only seven (9-2 = 7) valence electron pairs left to be drawn.

  • First, create lone pairs on oxygen atoms to represent the remaining valence electrons pair (outside atoms). On two oxygen atoms, six valence electron pairs have been indicated. There is still one valence electron pair left in the system at this point. The lone pair on the sulfur atom is designated as such.

  • In the drawing, all valence electron pairs are now labeled as bonds or lone pairs, depending on their configuration.

Atomic Charges

The presence of charges on atoms is critical in the search for the most stable structure. As a result, we must select the most stable structure to acquire the Lewis structure. As a result, if there are any changes, we should look into them.

Following the marking of electron pairs on atoms, it is necessary to label the charges of each atom. Each oxygen atom will get a -1 charge, whereas each sulfur atom will receive a +2 charge. SO2 is a neutral molecule, which means that the total charge of the molecule should be zero. It has a total charge of (-1) * 2 + (+2) = 0, which is equal to zero.

By Conversion of Lone Pairs to Bonds Increase the Stability

When there are positive and negative charges on a large number of atoms or higher charges (such as +2, +3, -2, -3) on atoms in an ion or molecule, the structure is not stable, and the charge distribution is not balanced. As a result, we should make every effort to lower the charges on atoms wherever feasible.

We are now going to lower the charges on these atoms in the manner described below.

  • We should now attempt to reduce the number of charges by transforming a lone pair or pairs into a bond. As a result, a lone pair on an oxygen atom is converted into a new S-O bond with the sulfur atom.

  • A double bond has formed between one oxygen atom and one sulfur atom at this point. As you can see, charges have been decreased as a result of the new structure.

  • Given the fact that atoms still have charges on them, we may attempt to turn a lone pair into a bond. As a result, a lone pair on another oxygen atom is converted into a bond with a sulfur atom. As a result, there are no charges on the atoms of sulfur and oxygen.

  • As a result, the Lewis structure of SO2 should be used for that structure.


Sulfur dioxide has a trigonal planar electron geometry, which means that it has three electrons per planar electron. There is an angle of 119 degrees between the three electron pairs that form the bond. Two double pairs are bonded together, and there is one lone pair as well, which further contributes to the bend form of the wire.

SO2 Molecular Geometry

We know that the molecule adopts a shape that minimizes the repulsions between electrical pairs to build the structure. SO2 has the same chemical geometry as Carbon Dioxide (CO2). Below, we shall demonstrate the bonding of SO2 without making any assumptions.

O === S=== O

Now, if we want to determine the precise molecular form of SO2, we must first understand the electron distribution between Sulphur and Oxygen. Sulfur contains six electrons at the outer level, whereas Oxygen has four, one for each link.

As a result, the total amount of 10 electrons in five pairs is ten. Four pairings are required to form bonds, leaving one pair alone. Each of the two double bonds has two pairs and is formed as a single unit.

Because the solitary isolated pair is not included in the shape description, we may deduce that the molecular shape of SO2 is V-Shaped or Bent. As a result, our first view of the original structure differs from the original.

SO2 Electron Geometry

so2 electron

SO2 has a trigonal planner-shaped electron geometry, which is generated by the electrons. The electrons are arranged on a plane with a 120-degree angle between the three pairs of bonding electrons. To join two pairs of doubles, one pair must remain alone. As a consequence, the object takes on a curved form.

Is SO2 Polar or Non-Polar?

We can determine that SO2 is asymmetrical when we analyze the Lewis structure since it has a region with varying sharing. Its molecular geometry is curved, meaning that the atoms of Oxygen at the top have a lower electronegativity while the atoms of Oxygen at the bottom have a higher electronegativity. The conclusion that can be drawn from this is that SO2 is polar.

SO2 Hybridization

In sulfur dioxide, hybridization occurs at the sp2 level. To do so, we will first examine the sulfur atom, which will serve as the center atom. When SO2 is formed, this center atom is connected to two oxygen atoms, forming the configuration O=S=O. Sulfur and the two oxygen atoms make one sigma and one pi connection. Additionally, the atom will accept one lone pair.

Let us dissect it further. When sulfur is in its ground state, the outermost shell has six electrons and the first two shells are likewise filled. The 3p portal has four electrons while the 3s orbital contains two paired electrons.

It now needs to create four bonds (with oxygen), which requires four unpaired electrons. This results in the formation of an excited state in sulfur, in which a single 3px electron jumps to the 3d orbital.

When this occurs, there will be one unpaired electron in each of the three 3d orbitals and three in each of the three 3p orbitals. The electrons that form the sigma bonds and the lone pair, on the other hand, are at distinct energy levels. When hybridization occurs, the stable state is reached.

Two 3p orbitals and one 3s orbital are hybridized during the process of hybridization. Three sp2 hybrid orbitals are formed in total. Two-hybrid orbitals will contain unpaired electrons, whereas the third hybrid orbital will contain the lone pair.

After forming sigma bonds with the oxygen atoms, these unpaired electrons are removed. Meanwhile, the 3d and 3p orbitals stay unchanged and play a role in pi bond formation. Interestingly, the oxygen atom in this molecule also undergoes sp2 hybridization.

SO2 hybridization results in the hybridization of two 3p orbitals and one 3s orbital. Two-hybrid orbitals will contain unpaired electrons, whereas one hybrid orbital will have a lone pair of electrons. The 3d and 3p orbitals stay unchanged, forming pi bonds.


Every atom exhibits sp2 hybridization. Each oxygen atom contains two lone pairs and one sigma bond. As a result, the hybridization of oxygen atoms should be sp2. There are two sigma bonds and one lone pair on the sulfur atom, which results in sp2 hybridization.

Frequently Asked Questions

Here are some FAQs related to Sulfur dioxide:

1. Why is SO2 composed of ten valence electrons?

Because sulfur now contains more than eight electrons, we say that it “expands octet.” Now that sulfur possesses six unpaired electrons, it is capable of forming six covalent bonds, totaling 12 electrons around its valence shell. Thus, in addition to being octet, sulfur can extend octet to include ten or twelve electrons.

2. SO2 has how many lone electrons?

Each sulfur atom contains one lone pair, whereas each oxygen atom has two. As a result, SO2 has a total of five lone pairs on the last shells of each atom.

3. How are valence electrons determined?

The electrical configurations of elements may be used to determine the valence electrons. Following that, the total number of valence electrons in an element is determined by the number of electrons in its outermost shell.

4. Is SO2 a covalent compound?

Sulfur dioxide, or SO2, is a colorless gas with an unpleasant odor. It is a molecule that is covalently bound. SO2 is composed of a double covalent link with one oxygen atom and a covalent bond with the other.

5. Why is SO2 an exception to the octet rule?

Due to the formal charge, the SO2 molecule can have a single or double bond. Since S is one of the elements that can violate the octet rule, SO2 should have a double bond. However, many prefer not to violate the octet rule because S in the Lewis structure, O=S=O, would be surrounded by ten electrons.

6. Is SO2 a curved or a linear gas?

Carbon dioxide is straight, but sulfur dioxide is bent (V-shaped). The two double bonds in carbon dioxide strive to be as far apart as possible, resulting in a linear molecule.

7. How is SO2 hybridization defined?

In sulfur dioxide, hybridization occurs at the sp2 level. To do so, we will first examine the sulfur atom, which will serve as the center atom. When SO2 is formed, this center atom is connected to two oxygen atoms, forming the configuration O=S=O.

8. How many electron groups does SO2 contain?

Each S atoms, as well as each oxygen atom, possesses six valence electrons. The Lewis electron structure is seen here with 18 valence electrons. Around the center atom, there are three electron groups, two double bonds, and one lone pair.

9. What is the SO2 coefficient?

The solely measured measurement for SO2 in the air is 0. 122 cm" sec-l (a = 5%), which Andrew14 reported at 20°C and 760 torrs. Andrew used two glass flasks, one of which contained air and the other of which contained SO2.

10. In chemicals, what is SO2?

Sulfur dioxide, SO2, is a colorless gas or liquid with a stench that is pungent and suffocating. It is created by the combustion of fossil fuels (coal and oil) and the smelting of sulfur-containing mineral ores (aluminum, copper, zinc, lead, and iron). Sulfur dioxide is a colorless gas that readily dissolves with water to generate sulfuric acid.


The polarity of SO2 has been detailed in this section, as well as the molecular geometry, electron geometry, Lewis structure, and bond angle (Sulfur Dioxide). If you want to learn more about anything, you may find a wealth of knowledge on this website.

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