Lewis Structure of HO2- (With 6 Simple Steps to Draw!)

I’m super excited to teach you the lewis structure of HO2- ion in just 6 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of HO2- ion.

So, if you are ready to go with these 6 simple steps, then let’s dive right into it!

Lewis structure of HO2- ion contains single bonds between the two Oxygen (O) atoms as well as between Oxygen (O) & Hydrogen (H) atom. The central Oxygen atoms have 2 lone pairs while the outer Oxygen atom has 3 lone pairs. The outer Oxygen atom has -1 formal charge.

Let’s draw and understand this lewis dot structure step by step.

(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of HO2- ion).

6 Steps to Draw the Lewis Structure of HO2- ion

Step #1: Calculate the total number of valence electrons

Here, the given ion is HO2- ion. In order to draw the lewis structure of HO2-, first of all you have to find the total number of valence electrons present in the HO2- ion.
(Valence electrons are the number of electrons present in the outermost shell of an atom).

So, let’s calculate this first.

Calculation of valence electrons in HO2- ion

• For Hydrogen: 

Hydrogen is a group 1 element on the periodic table. ^[1]

Hence, the valence electron present in hydrogen is 1 (see below image).

• For Oxygen:

Oxygen is a group 16 element on the periodic table. ^[2]

Hence, the valence electron present in oxygen is 6 (see below image).

Hence in a HO2- ion,

Valence electron given by each Hydrogen (H) atom = 1
Valence electrons given by each Oxygen (O) atom = 6
Electron due to -1 charge, 1 more electron is added
So, total number of Valence electrons in HO2- ion = 1 + 6(2) + 1 = 14

Step #2: Select the center atom (H is always outside)

While selecting the center atom, always put the least electronegative atom at the center.

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table). ^[3]

Here in the HO2, if we compare the hydrogen atom (H) and oxygen atom (O), then hydrogen is less electronegative than oxygen. But as per the rule, we have to keep hydrogen outside.

So, one of the oxygen atoms should be placed in the center and the remaining hydrogen and oxygen atoms will surround it.

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of HO2, put the two electrons (i.e electron pair) between the oxygen-oxygen atoms and oxygen-hydrogen atoms to represent a chemical bond between them.

These pairs of electrons present between the Oxygen atoms as well as between the Oxygen and Hydrogen atoms form a chemical bond, which bonds these atoms with each other in a HO2 molecule.

Step #4: Complete the octet (or duplet) on outside atoms. If the valence electrons are left, then put the valence electrons pair on the central atom

Don’t worry, I’ll explain!

In the Lewis structure of HO2, the outer atoms are hydrogen atoms as well as oxygen atom.

Hydrogen already has a duplet (see below image).

So now, you have to complete the octet on oxygen atom (because oxygen requires 8 electrons to have a complete outer shell).

Now, you can see in the above image that the oxygen atom forms an octet.

Also, only 10 valence electrons of HO2- ion are used in the above structure.

But there are total 14 valence electrons in HO2- ion (as calculated in step #1).

So the number of electrons left to be kept on the central oxygen atom = 14 – 10 = 4.

So let’s keep these four electrons (i.e 2 electron pairs) on the central oxygen atom.

Now, let’s move to the next step.

Step #5: Check whether the central atom has octet or not. If it does not have an octet, then convert the lone pair into double bond or triple bond

In this step, we have to check whether the central atom (i.e oxygen) has an octet or not. 

In simple words, we have to check whether the central Oxygen (O) atom is having 8 electrons or not.

As you can see from the above image, the central atom (i.e oxygen) has 8 electrons. So it fulfills the octet rule and the oxygen atom is stable.

Step #6: Check the stability of lewis structure by calculating the formal charge on each atom

Now, you have come to the final step and here you have to check the formal charge on oxygen atoms (O) as well as hydrogen atom (H).

For that, you need to remember the formula of formal charge;

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

• For Hydrogen:
  Valence electron = 1 (as it is in group 1)
  Nonbonding electrons = 0
  Bonding electrons = 2
• For central Oxygen:
  Valence electrons = 6 (as it is in group 16)
  Nonbonding electrons = 4
  Bonding electrons = 4
• For outer Oxygen:
  Valence electrons = 6 (as it is in group 16)
  Nonbonding electrons = 6
  Bonding electrons = 2

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

Let’s keep these charges on the atoms in the above lewis structure.

As you can see in the above sketch, there is one -ve charge on the outer oxygen atom, which indicates the -1 formal charge on the HO2 molecule.

Hence, the above lewis structure of HO2- ion is the stable lewis structure.

Each electron pair (:) in the lewis dot structure of HO2- ion represents the single bond ( | ). So the above lewis dot structure of HO2- ion can also be represented as shown below.

Related lewis structures for your practice:
Lewis Structure of C2HCl
Lewis Structure of S2O
Lewis Structure of BrCl3
Lewis Structure of NO2Cl
Lewis Structure of TeF4 

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