So you have seen the above image by now, right?
Let me explain the above image in short.
CSe2 lewis structure has a Carbon atom (C) at the center which is surrounded by two Selenium atoms (Se). There are 2 double bonds between the Carbon atom (C) and each Selenium atom (Se). There are 2 lone pairs on both the Selenium atoms (Se).
If you haven’t understood anything from the above image of CSe2 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of CSe2.
So let’s move to the steps of drawing the lewis structure of CSe2.
Steps of drawing CSe2 lewis structure
Step 1: Find the total valence electrons in CSe2 molecule
In order to find the total valence electrons in CSe2 molecule, first of all you should know the valence electrons present in carbon atom as well as selenium atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)
Here, I’ll tell you how you can easily find the valence electrons of carbon as well as selenium using a periodic table.
Total valence electrons in CSe2 molecule
→ Valence electrons given by carbon atom:
Carbon is group 14 element on the periodic table.  Hence the valence electrons present in carbon is 4.
You can see the 4 valence electrons present in the carbon atom as shown in the above image.
→ Valence electrons given by selenium atom:
Selenium is a group 16 element on the periodic table.  Hence the valence electrons present in selenium is 6.
You can see the 6 valence electrons present in the selenium atom as shown in the above image.
Total valence electrons in CSe2 molecule = valence electrons given by 1 carbon atom + valence electrons given by 2 selenium atoms = 4 + 6(2) = 16.
Step 2: Select the central atom
For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.
Now here the given molecule is CSe2 and it contains carbon atom (C) and selenium atoms (Se).
You can see the electronegativity values of carbon atom (C) and selenium atom (Se) in the above periodic table.
If we compare the electronegativity values of carbon (C) and selenium (Se) then the carbon atom is less electronegative.
So here the carbon atom (C) is the center atom and the selenium atoms (Se) are the outside atoms.
Step 3: Connect each atoms by putting an electron pair between them
Now in the CSe2 molecule, you have to put the electron pairs between the carbon atom (C) and selenium atoms (Se).
This indicates that the carbon (C) and selenium (Se) are chemically bonded with each other in a CSe2 molecule.
Step 4: Make the outer atoms stable
Now in this step, you have to check the stability of the outer atoms.
Here in the sketch of CSe2 molecule, you can see that the outer atoms are selenium atoms.
These outer selenium atoms are forming an octet and hence they are stable.
Also, in step 1 we have calculated the total number of valence electrons present in the CSe2 molecule.
The CSe2 molecule has a total 16 valence electrons and all these valence electrons are used in the above sketch of CSe2.
Hence there are no remaining electron pairs to be kept on the central atom.
So now let’s proceed to the next step.
Step 5: Check the octet on the central atom. If it does not have octet, then shift the lone pair to form a double bond or triple bond.
In this step, you have to check whether the central carbon atom (C) is stable or not.
In order to check the stability of the central carbon (C) atom, we have to check whether it is forming an octet or not.
Unfortunately, the carbon atom is not forming an octet here. Carbon has only 4 electrons and it is unstable.
Now to make this carbon atom stable, you have to shift the electron pair from the outer selenium atom so that the carbon atom can have 8 electrons (i.e octet).
But after shifting one electron pair, the carbon atom is still not forming an octet as it has only 6 electrons.
So again we have to shift one more electron pair from the other selenium atom.
After shifting this electron pair, the central carbon atom will get 2 more electrons and thus its total electrons will become 8.
You can see from the above picture that the carbon atom is forming an octet.
And hence the carbon atom is stable.
Now let’s proceed to the final step to check whether the lewis structure of CSe2 is stable or not.
Step 6: Check the stability of lewis structure
Now you have come to the final step in which you have to check the stability of lewis structure of CSe2.
The stability of lewis structure can be checked by using a concept of formal charge.
In short, now you have to find the formal charge on carbon (C) atom as well as selenium (Se) atoms present in the CSe2 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
For Carbon (C) atom:
Valence electrons = 4 (because carbon is in group 14)
Bonding electrons = 8
Nonbonding electrons = 0
For Selenium (Se) atom:
Valence electrons = 6 (because selenium is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4
From the above calculations of formal charge, you can see that the carbon (C) atom as well as selenium (Se) atom has a “zero” formal charge.
This indicates that the above lewis structure of CSe2 is stable and there is no further change in the above structure of CSe2.
In the above lewis dot structure of CSe2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of CSe2.
I hope you have completely understood all the above steps.
For more practice and better understanding, you can try other lewis structures listed below.
Try (or at least See) these lewis structures for better understanding:
|BrCl Lewis Structure
|AsCl3 Lewis Structure
|C2H2Br2 Lewis Structure
|SbCl5 Lewis Structure
|CH3SH Lewis Structure
|KrF4 Lewis Structure
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. He is a founder of Pediabay and is passionate about helping students through his easily digestible explanations.
Read more about our Editorial process.