Lewis structure of BrO3-

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The Lewis structure of BrO₃^– contains one single bond and two double bonds, with bromine in the center, and three oxygens on either side. The top oxygen atom has three lone pairs, the left oxygen atom and right oxygen atom has two lone pairs, and the bromine atom has one lone pair.

Plus, there is a negative (-1) charge on the top oxygen atom.

Steps

By using the following steps, you can easily draw the Lewis structure of BrO₃^–.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)
#5 Convert lone pair and calculate formal charge again (if formal charges are not closer to zero)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… bromine is a group 17 element and oxygen is a group 16 element. Hence, bromine has seven valence electrons and oxygen has six valence electrons.

Now BrO₃^– has one bromine atom and three oxygen atoms.

So the total number of valence electrons = valence electrons of bromine atom + (valence electrons of oxygen atom × 3)

And BrO₃^– has a negative (-1) charge, so we have to add one more electron.

Therefore, the total number of valence electrons = 7 + 18 + 1 = 26

• Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for bromine and oxygen as follows:

Electronegativity value of bromine = 2.96
Electronegativity value of oxygen = 3.44

Obviously, bromine is less electronegative than oxygen. Hence, assume that bromine is the central atom.

So now, put bromine in the center and oxygens on either side. And draw the rough skeleton structure for the Lewis structure of BrO₃^– something like this:

Also read: How to draw Lewis structure of NH₄⁺ (3 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since bromine is surrounded by three oxygens, use six electrons to show three chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 26 valence electrons. And in the above structure, we have already used six valence electrons. Hence, twenty valence electrons are remaining.

Two valence electrons represent one lone pair. So twenty valence electrons = ten lone pairs.

Note that bromine is period 4 element, so it can keep more than 8 electrons in its last shell. And oxygen is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are oxygens, so each oxygen will get three lone pairs. And the central atom (bromine) will get one lone pair.

So the Lewis structure of BrO₃^– looks something like this:

In the above structure, you can see that the octet is completed on the central atom (bromine), and also on the outside atoms. Therefore, the octet rule is satisfied.

Now calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of HNO (5 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For bromine atom

Valence electrons = 7
Nonbonding electrons = 2
Bonding electrons = 6

Formal charge = 7 – 2 – ½ (6) = +2

• For each oxygen atom

Valence electrons = 6
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 6 – 6 – ½ (2) = -1

Mention the formal charges of atoms on the structure. So the Lewis structure of BrO₃^– looks something like this:

In the above structure, you can see that the formal charges of atoms are not closer to zero. Therefore, convert lone pair and calculate formal charge again.

Also read: How to draw Lewis structure of BeH₂ (3 steps)

#5 Convert lone pair and calculate formal charge again

As mentioned earlier, bromine is a period 4 element, so it can keep more than 8 electrons in its last shell.

So convert one lone pair from the two oxygen atoms to make a new bond with the bromine atom. And then, the Lewis structure of BrO₃^– looks something like this:

Now one last thing we need to do is, calculate the formal charge again and check the stability of the above structure.

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For bromine atom

Valence electrons = 7
Nonbonding electrons = 2
Bonding electrons = 10

Formal charge = 7 – 2 – ½ (10) = 0

• For left oxygen and right oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

• For top oxygen atom

Valence electrons = 6
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 6 – 6 – ½ (2) = -1

Mention the formal charges of atoms on the structure. So the Lewis structure of BrO₃^– looks something like this:

In the above structure, you can see that the formal charges of atoms are closer to zero. Therefore, this is the most stable Lewis structure of BrO₃^–.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

Now BrO₃^– is an ion having a negative (-1) charge, so draw brackets around the above Lewis structure and mention that charge on the top right corner. And then, the Lewis structure of BrO₃^– looks something like this:

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Related

• Lewis structure of NH₄⁺
• Lewis structure of HNO
• Lewis structure of BeH₂
• Lewis structure of AlCl₃
• Lewis structure of CH₂F₂

External video

• BrO3- Lewis Structure: How to Draw the Lewis Structure for BrO3- – YouTube • Wayne Breslyn

External links

• Drawing the Lewis Structure for BrO3 – The University of Maryland
• Chemical Bonding: BrO3- Lewis Structure – The Geoexchange
• BrO3- lewis structure, molecular geometry, bond angle, polarity, electrons – Topblogtenz
• BrO3- Lewis Structure (Bromate Ion) – Pinterest
• Bromate (BrO3-) Ion Lewis Structure – Chemistry School
• Draw a Lewis structure for BrO₃^– that obeys the octet rule. Assign oxidation numbers to each atom – Homework.Study.com
• BrO3- Lewis Structure in 6 Steps (With Images) – Pediabay
• Draw the Lewis structures for BrO3- on a scratch paper and indicate the formal charges for Br and O’s – Chegg
• Lewis Structure of BrO3- – Laurence Lavelle
• Does the Lewis Structure for BrO₃^– have three double bonds or two double bonds? – Socratic
• VSEPR geometry of BrO3- – Reddit
• Draw one lewis structure (including all bonds and all non-bonding electron pairs/lone pairs) of BrO3 – (bromate ion) that follows the octet rule – Brainly
• Draw the Lewis structure for the bromate ion (BrO3) with minimized formal charges – Bartleby
• Draw the Lewis structure for BrO3 – Numerade