HSO4- Lewis Structure in 6 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

HSO4- lewis structure has a Sulfur atom (S) at the center which is surrounded by three Oxygen atoms (O) and one O-H group. Two Oxygen atoms (O) are double bonded with the Sulfur atom (S) and the other Oxygen atom (O) and O-H group is single bonded with the Sulfur atom (S). The single bonded Oxygen atom has -1 formal charge.

If you haven’t understood anything from the above image of HSO4- lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of HSO4- ion.

So let’s move to the steps of drawing the lewis structure of HSO4- ion.

Steps of drawing HSO4- lewis structure

Step 1: Find the total valence electrons in HSO4- ion

In order to find the total valence electrons in HSO4- ion, first of all you should know the valence electrons present in hydrogen atom, sulfur atom as well as oxygen 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 hydrogen, sulfur as well as oxygen using a periodic table.

Total valence electrons in HSO4- ion

→ Valence electrons given by hydrogen atom:

Hydrogen is group 1 element on the periodic table. ^[1] Hence the valence electron present in hydrogen is 1.

You can see that only 1 valence electron is present in the hydrogen atom as shown in the above image.

→ Valence electrons given by sulfur atom:

Sulfur is a group 16 element on the periodic table. ^[2] Hence the valence electrons present in sulfur is 6.

You can see the 6 valence electrons present in the sulfur atom as shown in the above image.

→ Valence electrons given by oxygen atom:

Oxygen is group 16 element on the periodic table. ^[3] Hence the valence electrons present in oxygen is 6.

You can see the 6 valence electrons present in the oxygen atom as shown in the above image.

Hence, 

Total valence electrons in HSO4- ion = valence electrons given by 1 hydrogen atom + valence electrons given by 1 sulfur atom + valence electrons given by 4 oxygen atoms + 1 more electron is added due to 1 negative charge = 1 + 6 + 6(4) + 1 = 32.

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 ion is HSO4- ion and it contains hydrogen atom (H), sulfur atom (S) and oxygen atoms (O).

So as per the rule we have to keep hydrogen outside.

Now, you can see the electronegativity values of sulfur atom (S) and oxygen atom (O) in the above periodic table.

If we compare the electronegativity values of sulfur (S) and oxygen (O) then the sulfur atom is less electronegative.

So here the sulfur atom (S) is the center atom and the oxygen atom (O) is the outside atom.

Step 3: Connect each atoms by putting an electron pair between them

Now in the HSO4 molecule, you have to put the electron pairs between the sulfur (S) & oxygen (O) atoms and between the oxygen (O) & hydrogen (H) atom.

This indicates that these atoms are chemically bonded with each other in a HSO4 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 HSO4 molecule, you can see that the outer atoms are hydrogen atoms and oxygen atoms.

These hydrogen atoms and oxygen atoms are forming a duplet and octet respectively and hence they are stable.

Also, in step 1 we have calculated the total number of valence electrons present in the HSO4 ion.

The HSO4 ion has a total 32 valence electrons and all these valence electrons are used in the above sketch.

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

In this step, you have to check whether the central sulfur atom (S) is stable or not.

In order to check the stability of the central sulfur (S) atom, we have to check whether it is forming an octet or not.

You can see from the above picture that the sulfur atom is forming an octet. That means it has 8 electrons.

And hence the central sulfur atom is stable.

Now let’s proceed to the final step to check whether the lewis structure of HSO4 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 HSO4.

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 hydrogen (H) atoms, sulfur (S) atom as well as oxygen (O) atoms present in the HSO4 molecule.

For calculating the formal charge, you have to use the following formula;

Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons

You can see the number of bonding electrons and nonbonding electrons for each atom of HSO4 molecule in the image given below.

For Hydrogen (H) atom:
Valence electron = 1 (because hydrogen is in group 1)
Bonding electrons = 2
Nonbonding electrons = 0

For Sulfur (S) atom:
Valence electrons = 6 (because sulfur is in group 16)
Bonding electrons = 8
Nonbonding electrons = 0

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 2
Nonbonding electrons = 6

For Oxygen (O) atom (of O-H group):
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
H	=	1	–	2/2	–	0	=	0
S	=	6	–	8/2	–	0	=	+2
O	=	6	–	2/2	–	6	=	-1
O (of OH group)	=	6	–	4/2	–	4	=	0

From the above calculations of formal charge, you can see that the sulfur (S) atom has +2 charge while the three oxygen atoms have -1 charges.

So let’s keep these charges on the respective atoms of the HSO4 molecule.

The above lewis structure of HSO4 is not stable. So we have to minimize these charges by shifting the electron pairs from the oxygen atoms to the sulfur atom.

After shifting the electron pairs from oxygen atoms to sulfur atom, the -1 charge still remains on the oxygen atom. This overall -1 charge on the HSO4 molecule is represented in the image given below.

In the above lewis dot structure of HSO4- ion, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of HSO4- ion.

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:

C2H2Cl2 Lewis Structure	NH2OH Lewis Structure
HClO3 Lewis Structure	SF5- Lewis Structure
C2Cl2 Lewis Structure	N2F2 Lewis Structure