CO2 Lewis Structure is the chemical bond between one atoms of Carbon and two molecules of Oxygen combined together to form carbon dioxide. This model was presented by Gilbert N Lewis who in 1916 presented article which used the dot and lines method to present the shared pairs.
Carbondioxide has one atom of carbon and two oxygen molecules which are bonded together. Carbon has a total of 6 electrons, two in its first orbit while the rest of four in the outer orbit. Oxygen has 8 electrons, two in the first orbit and 6 in the outer most orbit. There should ideally be a total of eight electron in each of the second orbit in every atom. When there is a lack of total number of electrons in the outer most orbit then it makes the atom reactive to complete its number of electrons.
The number of electrons in the outer most orbit in carbon and oxygen both gives the perfect environment to combine and form a molecule of carbondioxide. Carbon needs four more electrons to complete its outer most shell while oxygen needs two more electrons. So a carbon and two oxygen combine to form a bond. The electrons in the outer most shell of carbon are represented by 4 dots and the electron in oxygen’s outer most shell are presented by 6 dots. In the diagram which shows the bonding is depicted through the use of lines and each line denotes the bond between the atoms. In case of CO2 the bond has two lines on either sides of Carbon.
Carbon C and Oxygen O complete the number of electrons around each outer most shell by sharing their electrons. The two lines on side of C show that there is a double bond between the two. In this way both of their electron number is completed thus giving them stability.
Lewis structure
Lewis structure pictorially presents the valence electrons in atoms and the bonding among the molecules. The dots present the number of valence electrons and the dashes or lines present the number of bonding in the molecules. It does not show how the bonds are formed rather it serves the purpose of presenting the electronic configuration which is satisfaction of octet rule and charges on the atoms.
How to draw Lewis Structure
Lewis structure is defined by following example of NO3.
· The valence electrons or the number of electrons in each of the atom should be known in case of NO3- . They are the sum of group number of all the atoms and their charge.
N=5
O (x3) = 18
Charge = 1
24
· A structure will be formed in which the central atom will be the one making the most bonds with other atoms. Nitrogen N will be in the centre of the skeletal structure and Oxygen O will be at the three sides.
· The lone pair of electrons on oxygen are 24. Out of them 6 are used in making the skeletal structure. To complete the octet electrons the lone pairs of terminal atoms should be added.
· The remaining electrons should be used to complete the octet of atom in the centre. With no electrons on the sides the electrons of the central atom can be taken by making multiple bonds. Here when Nitrogen N has two lesser electrons then the electrons of one Oxygen O will be used to complete the octet.
· Formal charges calculation is the next step, for which the group number of atoms is subtracted with half of number of bonding electrons subtracted with number of lone pair electrons.
We should know the minimum number of possible formal charges which means for as many atoms the formal charge 0 is possible
The positive charge will be according to the electronegativity. The positive charge will be on the lesser electronegative atom while negative charge on more electronegative atom.
If the adjacent atoms have +1 and -1 charge then they can be removed by taking the lone pair of electrons from -1 to make a double or a triple bond with +1 charge atom. Since we are talking about N here which has only two shells so octet will be of 8 only for atoms of more shells the sum of octet will also increase.
· The best Lewis structure is formed when the octet is complete and the lowest possible charge is attained. Most commonly the way of indicating the structure is use of lines for bonding pairs and the charges can be shown as nets charges rather all of the charges.
The Lewis structure can be drawn in different ways depending upon what the chemist is trying to show. However there are more than just Lewis structure that needs to be understood here.
Molecular Geometry
It is the three dimensional structural presentation of arrangement of atoms in a molecule. It determines the biological activity, magnetism, colour, phases of matter and polarity. This is where the Lewis structure helps us in understanding the shape of a molecule by determining its pairs and bonds. The job is not completely done here and another theory is applied called Valence Shell Electron Pair Repulsion Theory (VSEPR). This will define the molecular geometry and electron group geometry.
There is another phenomenon that works in electron geometry which is the bond angle. Lewis structure helps in understanding the valence electrons which has already been discussed.
Valence Shell Electron Repulsion Theory
Lewis structure helps in understanding the valence electrons in the central atom. The valence shell electron repulsion theory says that the pairs of electron repel each other even if they are in a bond pair or lone pairs. Therefore the electron pairs will go as far as possible from each other to minimize this repulsion. The focus of VSEPR is on the electron pairs and electron groups both. Electron group can be a double or triple bond, single unpaired electron, lone pair or electron pair. The shape of the molecule will this be predicted using the theory determine the bond pair and lone pair on atom in the centre.
The electrons on an atom the location of nuclei determines the shape of molecule. Both the electron and nuclei get into positions that will maximize attraction and minimize repulsion. In order to establish a state of equilibrium with the system having the lowest possible energy the shape of molecule is important. Molecular geometry and electron group geometry both combine to predict the shape of the molecule. The electron group number determines the geometry of electron group.
Electron groups Electron group geometry
2 Linear
3 Trigonal planar
4 Tetrahedral
5 Trigonal bipyramidal
6 Octahedral
Electron groups and lone pairs both define the molecular geometry. Electron group geometry is named after bond pairs as mentioned above.
What are the properties of Carbon?
Carbon has a unique property due to which it can form chain of bonds with other elements thus inculcating distinctive features to other components as well. Its chemical properties are also different from the rest. At place when it is considered responsible for carbon footprint and global warming, other of its usages makes it of vital importance in daily life.
The biggest and most important bonding occurs with carbon is that of hydrogen. The chains it forms makes the basis of organic chemistry which specifically deals with this field. More than a million organisms’ basic structure is that of organic component. Another most important organic compound made through carbon is petroleum and its products which is fuelling the modern industry and world as we know of it. Carbon also makes inorganic compounds as well but that are very lesser in number.
The element carbon exclusively exists in two crystalline form, graphite and diamond. Other forms are black fume and vegetal carbon. Pure form of carbon can also be prepared by decomposing sugar in the absence of air. The chemical and physical properties vary in different crystalline structures. Elemental carbon is inert and insoluble in different solutions including acids and bases organic solvent and water. When the temperature is high it will combine with oxygen to form carbon dioxide or carbon monoxide. It reacts with metals to form carbide and makes metallic acid with potassium nitrate and nitric acid. Fluorine is the only halogen that reacts with elemental carbon.
Carbon in the form of diamond is the hardest substance in the world and with graphite it is used mostly in the industry and daily usage. It is spread all around in the nature in many forms making 0.032% of the earth crust. It can be found in the form of hard coal and amorphous form in carbon-hydrogen-nitrogen in complex compound. This amount of carbon in environment is ever increasing with burning fossil fuels and emission of methane. Carbon has formed the basis of life with stable continuous bonds making the structural basis of living cells.
What are the properties of oxygen?
Oxygen is a non-metallic element belonging to 16th group of the periodic table. It is tasteless, odourless and colourless and the most essential for living organisms be it animal or plants. Animals take in oxygen which is then utilized in numerous body functions. As for the plants they are responsible for manufacturing oxygen through the process of photosynthesis in the presence of sun. They utilized the same oxygen at night for various functions of plants.
Oxygen plays an important part in combustion as well in which it helps making light and fire by combining with different elements and giving away heat as a reaction. Most important compound however is the life giving water.
Oxygen occupies 46% of the earthly mass while its presence in air comprises of 21% and 89% is present in the seawater. Its compounds can be found in the form of oxides, (acidic and basic), phosphates, aluminates, silicates, carbonates and sulfates. However they are not sources of oxygen because decomposing them and extracting oxygen from them is very expensive.
Oxygen can be obtained from air through distillation or fractional liquefaction and applied in manufacturing, refining and melting of various metals and steel. Oxidation helps in manufacturing of chemicals. It also helps processes like rocket propulsion and life support system in biology and medicine. Glass production, manufacturing of stones and mining are other usages of oxygen. The oxygen supply given in case of emergency in airplanes is in the form of sodium chlorate.
DNA and other important biological compounds and the importance is so important that animals needs it every second to breathe it for survival. The haemoglobin in the blood takes up the oxygen and supplies it to every cell of the body. The oxygen in the blood then uses that oxygen for respiration and giving away the energy required for survival.
In case of exposure to a large amount of oxygen it is damaging to the lungs as well. Those who are exposed to larger amounts of oxygen should get their lungs function test so they are able to know the functioning of their lungs. It is also stored at lower temperatures so to get access to it special clothes should be worn so that a person does not freeze.
Oxygen is also responsible for combustion on a scale much larger like wild fires because of higher concentration in the environment. A fire erupted in the Apollo 1 and spread so quickly that it was not able to be controlled. It was attributed to the presence of pure oxygen not with one third of atmospheric pressure rather normal atmospheric pressure.
What are the properties of carbon dioxide?
Carbon dioxide is a colourless gas with slight faint odour and sour taste. The presence of this gas is very little in the atmosphere but in fact have a powerful impact being a crucial part in the greenhouse. The emission of carbon dioxide in the environment more than required is causing global warming and the increase of carbon footprint is overall bringing changes drastic changes in the climate. In industries its manufacturing results as a by product from the making of limekilns or ammonia.
Its frozen form it is called dry ice which has variety of usages especially where the ice from water cannot stand. It is used frequently in refrigeration, inflating life jackets, blasting coal, fire extinguishers. It promotes plant growth in greenhouses and forming plastics and rubber. Carbonated beverages and immobilize animals before their slaughter. The gas does not help in combustion of most of the materials but it can ignite magnesium. 5% or more concentration of carbon dioxide may lead to unconsciousness and death.
So there’s more to carbon dioxide than CO2 Lewis structure. The bubbles coming out of a fizzy drink are due to carbon dioxide being dissolved in water. This process is reversible as well so as the pressure drops the gas releases itself. Its utility in fire extinguishers is because of the fact that it is denser than gas thus cutting of the supply of oxygen for combustion and then putting out the fire. Despite of its many usages its increasing emission is an alarming sign. All the harmful rays sent by sun are reflects back towards the space which had kept a balance in the earth’s atmosphere. Due to a blanket of carbon dioxide in the atmosphere the rays are not reflected back and dispersing in space which is increasing the earth’s temperature. Therefore more and more effects are needed to be put in to reverse the effect of carbon footprint in the environment.
What are the types of chemical bonding?
A chemical compound results in chemical bonding when two or more atoms come together to form a link keeping the atoms together.
An atom should have a complete octet ideally which means that there is a certain number of electrons in each of the orbits around the nucleus. However apart from the inert gases none of the atom has complete number of electrons which gives them the affinity to attract with other atoms and form bonds. Everything surrounding us is composed of atoms and all of the different compounds present naturally or artificially are all result of these chemical bonding. Water is a strong bond between two atoms called oxygen and hydrogen. Some of the atoms may be too reactive while other mild and some turn out to be less. Chemist play with these elements and have devised the following types of bonding
Lewis theory of chemical bonding
According to the Lewis theory an atom can be considered a Kernel which is positively charged which includes outer shell, nucleus and electrons. Outer shell can have a maximum of eight electrons. The corner of the cube surrounding the Kernel have those eight electrons. These presence of eight electrons demonstrate a stable configuration. This stability has to be achieved because mot every atom has those eight electrons in the outer most shell. Chemical bonding is the answer to it and atoms gain the stability when they either share their atoms with each other or give or take their atoms from one another. Not all electrons in the atom take part in the chemical bonding process rather the ones in the outer most shell do the business. These electrons are the valence electrons which can be demonstrated like earlier in CO2 Lewis structure. The valence of each element is either equal to the dots surrounding the elements in the Lewis structure or the number of dots subtracted by eight.
Kossel’s theory of chemical bonding
There are two types of elements in the periodic table. Noble gases are something which are totally non reactive. Apart from them the two types are the halogen which are at one extreme of the periodic table and are electronegative because they tend to gain an electron. As the electron is given to them their over all charge becomes negative. While on the outer extreme are the alkali metals which are highly electropositive. As a result of losing an electron they become positive. Due to the charges on these halogen and alkali metals they become highly reactive and since positive and negative attracts these atoms also come together and form a bond with each other. This is why the noble gases do not reach with each other and they stay inert because they have stable configuration. Only those atoms or elements come together and form bonding which do not already have a stable configuration and want to achieve it.
Types of chemical bonding
Ionic bonding
Iconic bond has transfer of electrons from one atom to another. There are elements which have an affinity for a particular element. This helps them in achieving stability and forming a strong bond. The ionic bond result when two atoms of positive and negative charge come together to bond. This is one of the strongest bonds developed between two elements because of the strong attraction between opposite charges.
Covalent bonding
This bonding is about sharing of electrons. The electrons of one atom are now shared with other one as well. This type of bonding is seen in the organic compounds as well which form the basis of life structure. This molecule formed now has electrons which circulates around the two nuclei of the atoms. The bonding in methane CH4 is one form of covalent bonding.
Polar covalent bonding
Water is an example not polar covalent bonding. In this type the electrons are not equally shared. One of the atom will have a higher charge than the other. As a result the more electronegative atom will attract the electron towards itself. This is polar covalent bonding. Now one end of the element will have a positive while the other end will have a negative charge. This difference arises because the electrons are not equally distributed through the entire molecule rather due to the uneven attraction one part will be more positive/negative than other.
Hydrogen bonding
Hydrogen has a unique property that it has only one electron and one proton. Unlike all other elements in the periodic table they lack a neutron. Hydrogen bonding involves hydrogen in it which is a weaker bonding as compared to ionic. It is similar to polar covalent bonding with hydrogen being involved in it, it has a positive charge on it and the other molecule oxygen has a more negative charge so attracts the electrons towards it more. The reason for hydrogen having lesser positive charge is the distribution of protons in either of nuclei. Hydrogen contains just one proton while oxygen has more thus it is able to attract the electrons much easily. This bonding in water gives it its unique properties also.
What factors affect bonding?
Bond length
When the process of chemical binding is taking place the atoms are coming close to each other. When they are getting closer the potential energy continues to decrease and when they are closest the potential energy is at its minimum. However getting much closer repulsion starts to take place thus increasing potential energy again. At an equilibrium distance the atoms vibrate at their place. This distance between the nuclei of two atoms bonded with each other is the Bond length. When the bond length decreases the strength of chemical bond increases as the bond length increases the bonding signifies weakness.
Bond enthalpy
Energy is either released or absorbed by the atoms when they come close together to form a bond. In case of breaking the bond as well energy is required so the amount of energy needed to separate the molecules from each other. This energy is the bond enthalpy or bond Dissociation enthalpy. The bond strength is defined by bond enthalpy as well. The greater the bond enthalpy the greater is strength.
London Dispersion Force
London dispersion forces are weaker in magnitude and it arises due to the temporary imbalance in the charges of atoms. For this reason when there are poles formed on the atoms it creates an attraction among them this bringing them together.
What factors effect bonding?
The factors that effect stability in bonds depends upon the types of bonds.
Ionic crystal’ stability is defined by the lattice energy which is required to bring the atoms together and is defined by the attraction between the ions.
In coordination compounds the stability is defined through electronic structure, dimensions and degree of oxidation.
Overall the stability can be defined by low centre of mass as well in which stability increases with low centre of mass. The size of base support increases thus increasing the stability as well. Another factor important for stability is the line of gravity and increased inertia or body mass.
The ionic bonds’ stability is determined by the valence electron the more an atom is able to compete its octet the more stability occurs between the elements.
For complexes the factors affecting stability are stearic effect or stearic hindrances, resonance effect, macrocyclic effect, chelating effect, nature of the ligand and nature of the central metal ion.
Summary
Chemical bonding forms the structure of life. Atom being the very fundamental unit of each and everything in life makes the driving force of life. Studying it reveals that it has many aspects which defines the minute details in it are only giving many surprises. CO2 Lewis structure is one example of atoms bonding depicting that at atomic level it by look simple to create bonding but there are many aspects which need to be considered. It starts from calculating the number of valence electrons and then their charges on each atom.
For understanding the Lewis structure the atoms and their basic structure needs to be understood and how the electrons help out in bonding with each other. Each atoms seeks stability and in attempt to this form different bonding. These bonding result in different compounds and gives chemist a chance to bring about newer in innovative things in the field. It is definitely an interesting field which will help in understanding that how the natural phenomenon starts from the very basic structures and their connections with each other bring about the entire beauties of the world.
Frequently asked questions
What are the rules for Lewis Structure?
Single, double, triple bonding, lone pairs and unpaired electrons determine the position of valence electrons on each atom in the Lewis structure. All elements obey the octet rule especially who have two shells in their atom after which they have eight electrons in total except for hydrogen.
Why are Lewis structure important?
Lewis structure defines the bonding between the atoms through a dot or line presentation. This is not just limited to diagrams but it also helps in predicting the reactivity, polarity and geometry of the chemical bonding.
What makes a good Lewis structure?
Lewis structure are completed through the use of formal charges a without placement and use of these formal charges and these are also required in the minimum quantity as possible.
What is a stable Lewis structure?
Formal charges define the strength of a Lewis structure. The bond in which the charges are closest to zero makes the most stable Lewis structure.
Do ionic bonds share electrons?
Ionic bonds transfer electrons from one atom to another while it is the covalent bond that shares the electrons with each other.
What is an octet?
In chemistry octet is the arrangement of electrons in the outer shell of the noble gases with a number 8. This brings in the inertness in these gases because this makes them non-reactive. Any other atom that is close to this configuration is highly reactive and will try and attempt to achieve the octet. As a result to this different bonds are formed. If we speak of the halogens which lie next to noble gases the configuration in the outer cell is less than one which makes them instable and in order to gain stability they a readily available to react with other elements who can help them complete their octet.
What is a duplet?
An octet attains the configuration of eight electrons in the outer most shell. In case of a duplet a configuration of two electrons is required in the outer most shell to form stability.