HO2- 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.

HO2- lewis structure has a single bond between the two Oxygen atoms (O) as well as between the Oxygen atom (O) and Hydrogen atom (H). There are 2 lone pairs on the central Oxygen atom (O) and 3 lone pairs on the outer Oxygen atom (O). There is a -1 formal charge on the outer Oxygen atom (O).

If you haven’t understood anything from the above image of HO2- lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of HO2- ion.

So let’s move to the steps of drawing the lewis structure of HO2- ion.

Steps of drawing HO2- lewis structure

Step 1: Find the total valence electrons in HO2- ion

In order to find the total valence electrons in HO2- ion, first of all you should know the valence electrons present in hydrogen 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 as well as oxygen using a periodic table.

Total valence electrons in HO2- 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 oxygen atom:

Oxygen is group 16 element on the periodic table. ^[2] 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 HO2- ion = valence electrons given by 1 hydrogen atom + valence electrons given by 2 oxygen atoms + 1 more electron is added due to 1 negative charge = 1 + 6(2) + 1 = 14.

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 HO2- ion and it contains hydrogen atom (H) and oxygen atoms (O).

You can see the electronegativity values of hydrogen atom (H) and oxygen atom (O) in the above periodic table.

If we compare the electronegativity values of hydrogen (H) and oxygen (O) then the hydrogen atom is less electronegative. But as per the rule we have to keep hydrogen outside.

So consider one of the oxygen atoms (O) as the center atom and the hydrogen atom (H) & other remaining oxygen atom (O) are the outside atoms.

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

Now in the HO2 molecule, you have to put the electron pairs between the oxygen-oxygen atoms and between the oxygen-hydrogen atoms.

This indicates that these atoms are chemically bonded with each other in a HO2 molecule.

Step 4: Make the outer atoms stable. Place the remaining valence electrons pair on the central atom.

Now in this step, you have to check the stability of the outer atoms.

Here in the sketch of HO2 molecule, you can see that the outer atoms are hydrogen atom and oxygen atom.

These hydrogen atom and oxygen atom 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 HO2- ion.

The HO2- ion has a total 14 valence electrons and out of these, only 10 valence electrons are used in the above sketch.

So the number of electrons which are left = 14 – 10 = 4.

You have to put these 4 electrons on the central oxygen atom in the above sketch of HO2 molecule.

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 oxygen atom (O) is stable or not.

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

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

And hence the central oxygen atom is stable.

Now let’s proceed to the final step to check whether the lewis structure of HO2 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 HO2.

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) atom as well as oxygen (O) atoms present in the HO2 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 HO2 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 central Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

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

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
H	=	1	–	2/2	–	0	=	0
O (central)	=	6	–	4/2	–	4	=	0
O (outer)	=	6	–	2/2	–	6	=	-1

From the above calculations of formal charge, you can see that the outer oxygen (O) atom has -1 charge and the other atoms have 0 charges.

So let’s keep these charges on the respective atoms in the HO2 molecule.

This overall -1 charge on the HO2 molecule is represented in the image given below.

In the above lewis dot structure of HO2- ion, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of HO2- 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:

C2HCl Lewis Structure	S2O Lewis Structure
BrCl3 Lewis Structure	NO2Cl Lewis Structure
TeF4 Lewis Structure	ClF Lewis Structure