So you have seen the above image by now, right?
Let me explain the above image in short.
BeH2 lewis structure has a Beryllium atom (Be) at the center which is surrounded by two Hydrogen atoms (H). There are 2 single bonds between the Beryllium atom (Be) and each Hydrogen atom (H).
If you haven’t understood anything from the above image of BeH2 (beryllium hydride) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of BeH2.
So let’s move to the steps of drawing the lewis structure of BeH2.
Steps of drawing BeH2 lewis structure
Step 1: Find the total valence electrons in BeH2 molecule
In order to find the total valence electrons in a BeH2 (beryllium hydride) molecule, first of all you should know the valence electrons present in beryllium atom as well as hydrogen 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 beryllium as well as hydrogen using a periodic table.
Total valence electrons in BeH2 molecule
→ Valence electrons given by beryllium atom:
You can see the 2 valence electrons present in the beryllium atom as shown in the above image.
→ Valence electrons given by hydrogen atom:
You can see that only 1 valence electron is present in the hydrogen atom as shown in the above image.
Total valence electrons in BeH2 molecule = valence electrons given by 1 beryllium atom + valence electrons given by 2 hydrogen atoms = 2 + 1(2) = 4.
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.
(Remember: If hydrogen is present in the given molecule, then always put hydrogen outside.)
Now here the given molecule is BeH2 (beryllium hydride) and it contains beryllium atom (Be) and hydrogen atoms (H).
You can see the electronegativity values of beryllium atom (Be) and hydrogen atom (H) in the above periodic table.
If we compare the electronegativity values of beryllium (Be) and hydrogen (H) then the hydrogen atom is less electronegative. But as per the rule we have to keep hydrogen outside.
So here the beryllium atom (Be) is the center atom and the hydrogen atoms (H) are the outside atoms.
Step 3: Connect each atoms by putting an electron pair between them
Now in the BeH2 molecule, you have to put the electron pairs between the beryllium atom (Be) and hydrogen atoms (H).
This indicates that the beryllium (Be) and hydrogen (H) are chemically bonded with each other in a BeH2 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 BeH2 molecule, you can see that the outer atoms are hydrogen atoms.
These outer hydrogen atoms are forming a duplet and hence they are stable.
Also, in step 1 we have calculated the total number of valence electrons present in the BeH2 molecule.
The BeH2 molecule has a total 4 valence electrons and all these valence electrons are used in the above sketch of BeH2.
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 stability of the central atom
In this step, you have to check whether the central beryllium atom (Be) is stable or not.
Now beryllium requires only 4 electrons to become stable. The s-orbitals of beryllium get completely filled by these 4 electrons.
You can see from the above picture that the beryllium atom has 4 electrons and hence it is stable.
Now let’s proceed to the final step to check whether the lewis structure of BeH2 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 BeH2.
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 beryllium (Be) atom as well as hydrogen (H) atoms present in the BeH2 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
For Beryllium (Be) atom:
Valence electrons = 2 (because beryllium is in group 2)
Bonding electrons = 4
Nonbonding electrons = 0
For Hydrogen (H) atom:
Valence electron = 1 (because hydrogen is in group 1)
Bonding electrons = 2
Nonbonding electrons = 0
From the above calculations of formal charge, you can see that the beryllium (Be) atom as well as hydrogen (H) atom has a “zero” formal charge.
This indicates that the above lewis structure of BeH2 is stable and there is no further change in the above structure of BeH2.
In the above lewis dot structure of BeH2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of BeH2.
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:
|HNO lewis structure
|NI3 lewis structure
|CH2F2 lewis structure
|CH3- lewis structure
|I2 lewis structure
|ICl3 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.
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