Bromate ion (BrO3–) contains one bromine atom and three oxygen atoms. This article is about the Lewis structure, the Molecular geometry, Hybridization, MOT diagram, and the formal charge present on BrO3–.
What is Lewis’s structure and why it is important to study Lewis’s structure?
The valence shell electrons of a molecule are depicted in a Lewis Structure, which is a simplified representation. It’s used to illustrate how electrons in a molecule are distributed around specific atoms.
When two atoms are bonded, electrons are shown as “dots” or as a line between them. The main goal of Lewis Structure is to find the “optimal” electron configuration, which requires that the octet rule and formal charges be maintained.
The Lewis structure was initially proposed by famous scientist Gilbert N Lewis in his journal “The Atom and the Molecule” in 1916. The Lewis structure is important in chemistry because it can predict the number of bonds, nonbonding electrons, and bonding electron structure.
Lewis structure in chemistry does not try to explain the molecular shape, bond formation, or electron sharing between atoms. It is the most basic and limiting explanation of the electrical structure.
Introduction
One bromine atom and three oxygen combine to form the bromate ion. Bromate (BrO3– ) is a Br oxo anion.
Valence Electrons:
Valence electrons are the electrons in an atom’s outermost shell or energy level. To study the Lewis Structure of any molecule, it is very important to understand the electrons present in the valence shell.
Lewis Structure of Bromate ion (BrO3–):
Any molecule’s Lewis Dot structure is a graphical representation of the atoms that make up the structure and their respective valence electrons. This structure enables us to understand the molecule’s bond forms and electron arrangement.
To learn about the Lewis structure of bromate ions, we must first learn about the Lewis diagrams of the atoms involved. Bromate ion has an atomic number of 35 and an electronic configuration of 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5.
To study the Lewis structure, it is very important to understand the total number of valence shells present in the outer shell.
In the case of BrO-3, there are two double and one single bond exists between bromine and oxygen atom. Bromine is the central atom which is surrounded by oxygen atoms. Bromine contains one lone pair while a -1 charge is present on the bromine atom.
Steps to remember while drawing Lewis Structure:
To draw a Lewis structure of a molecule, there are a few general steps to follow. The number of steps can be adjusted depending on the molecule or ion’s complexity. We’ll look at each stage of drawing the Lewis structure of BrO-3 now.
Calculate the total number of electrons in the valence shells of the Bromine and oxygen atoms.
Total electron pairs exist as lone pairs and bonds.
Choosing the center atom
Draw lone pairs.
Mark charges on atoms
To acquire the optimum Lewis structure, check the stability and decrease charges on atoms by converting lone pairs to bonds.
Calculate the total number of electrons in the valence shells of the Bromine and oxygen atoms.
To draw the Lewis structure first we have to Calculate the valence electrons present in the Bromate ion (BrO3– ). In the case of bromine, we can see from the periodic table that bromine belongs to the seventh group of elements so seven electrons are present in the valence shell of an atom and there are 4s2 and 4p5 shells that are participating in bond formation.
While oxygen contains six valence electrons. As it belongs to six groups of the periodic table which we can see from the figure given below:
There are six electrons present in the valence shell of the atom.
There are three oxygen atoms present in the bromate ion so 6*3=18 valence electrons of oxygen and seven of bromine resulting in a total of 25 and one extra electron will be added here because of -1 charge results in a total of 27 valence electrons of the Bromate ion (BrO3-1).
Valence electron of bromine= 7
Valence electrons of oxygen= 6*3
Electron because of -1 charge= 1
=7+6*3+1
=7+18+1
=26
How many total valence electron pairs are present?
The second step of Lewis’s structure of BrO3-1 is to find out how many total valence electron pairs exist. The total valence electron pair means the sigma and pie bonds, which can be determined by dividing the total valence electrons present by two. For example, Total valence electron pairs in BrO3-1 are 13 as 26/2= 13.
Choosing the Center Atom
Being the core atom of a molecule has its own set of criteria. The most significant aspects of being the center atom are having a high valence and being the most electropositive atom.
The least electronegative atom must be placed in the center. So, the central atom is bromine because it is less electronegative than oxygen.
Draw Lone Pairs on Atoms
The next step after choosing the central atom is to draw lone pairs on the atoms of a molecule. To draw lone pairs, it is important to remember how many total numbers of electrons are present. so, in the case of Bromate ion (BrO3– ), there are 26 electrons present while six electrons are participating in a single bond between bromine and oxygen.
Now ten lone electrons pairs are present which are to be marked. Three lone pairs will be marked on each oxygen atom while the remaining two will be marked on bromine as shown in the figure given below:
From the figure above it can be seen that there are three sigma bonds (B-O) present while 10 lone pairs can be marked on Bromine and Oxygen atoms.
Mark and Stabilize Charges on Atoms
In the case of BrO3-1, +2 charge is present on bromine while -1 charge is present on each oxygen.
As the charges are present on each atom so the structure is unstable. To convert it into a stable it is necessary to convert the lone pairs to bonds which make it a stable structure.
The first step is the conversion of lone pair to a covalent bond.
The next step is again conversion to a covalent bond to reduce the further charges.
In the end, only one -1 charge remains on the oxygen atom which cannot be reduced further.
Molecular Geometry and Shape of the Molecule
Molecular Geometry of Bromate ion (BrO3– )
Molecular geometry or molecular structure refers to the three-dimensional shape or arrangement of atoms in a molecule. Understanding a compound’s molecular structure can help to determine its polarity, reactivity, phase of matter, color, magnetism, and biological activity.
The geometry of BrO3-1 is trigonal pyramidal
Molecular Structure or Geometry of BrO3–
The Geometry of BrO3-1 Molecule by AXN Notion:
The basic geometry of the molecule or ion will be described using the AXN notation, where A represents the core atom which is Bromine in this case and X represents the terminal atoms that bond to the central atom which is oxygen. The number of lone pairs is indicated by the letter “n ” which is ten in the case of Bromate ion (BrO3– ).
Bond Angle and Shape of BrO3–
In BrO3-1 the bond angle is 104o because of the repulsion of the lone pairs. While the structure is trigonal pyramidal.
Bond Angle Of Bromate ion (BrO3– )
Hybridization of BrO3–
The orbitals involved and the bonds produced during the interaction of bromine and oxygen molecules will be examined to determine the hybridization of the Bromate ion (BrO3– ).
Hybridization in BrO3-1 is sp3 because a three-sigma bond and one lone pair are involved in overlapping.
It is clear from the box diagram of the Bromate ion (BrO3– ) Lewis structure that the π bond cannot be considered in hybridization. There are only sigma bonds involved.
In the ground state of Br, there are five electrons in the 4p orbital, two electrons are transported to the 4d orbital, and two electrons are present as lone pairs in the 4s orbital.
Three new hybrid sigma bonds and one lone pair are formed when the three unpaired electrons in the 4p orbital join with three oxygen atoms.
In this case, the hybridization involves one s and three p orbitals, resulting in an sp3 hybrid orbital. Both Br and O can complete their octet by combining orbitals.
When does the hybridization process occur?
It is essential to realize that hybridization occurs when atomic orbitals of a similar energy mix and overlap like that of an s orbital with a p orbital or a s orbital with a d orbital.
Within a molecule, energy redistribution occurs among similar energy orbitals of individual atoms, resulting in the creation of new hybrid orbitals of equivalent energy.
The polarity of Compound and Factors Affecting Polarity .
The Polarity of Bromate ion (BrO3– )
When we examine a compound’s structure and properties in-depth, the polarity of the compound is a significant topic of discussion.
The separation of electric charge that results in one negatively charged end and one positively charged end is known as polarity.
Because of the difference in the electronegativity values of the involved atoms, this charge separation causes a net dipole moment on the overall molecule.
The strength with which a molecule attracts a shared pair of electrons towards itself is determined by the value of its net dipole moment, which can be positive or negative.
A molecule’s polarity or non-polarity can be determined by the value of its dipole moment.
We can observe that the Lewis structure of Bromate ion (BrO3– ) is a trigonal pyramidal form, which is an asymmetric molecule with a resultant dipole moment.
As it works from less electronegative to more electronegative substituents, the dipole moment acts from Br to O.
There’s a resulting dipole moment present in this configuration. As a result, the molecule is polar.
Factors Affecting Polarity
Electronegativity:
The stronger the atom’s ability to attract bound electrons, the higher its electronegativity. As a result, the difference between the electronegativity of atoms is precisely proportional to the polarity of a molecule.
Dipole Moment:
The dipole moment is a measurement used to find out the level of polarity. A molecule’s polarity increases as its dipole moment increase.
A molecule’s polarity and dipole moment are proportional.
Geometrical Shape:
A molecule’s geometrical shape plays a significant role in defining its polarity. The molecules that have a symmetrical form have a dipole moment of zero. When a molecule has a polar bond, the molecules’ dipole moments cancel out, resulting in a nonpolar molecule.
Characteristics of Bromate ion (BrO3– )
Chemical Formula | Bromate ion (BrO3– ) |
Boiling point | 100°C |
Melting point | 0°C |
Vapour pressure | 328 mmHg |
Molecular weight | 167.01 g/mol |
Density | 1,00 g/ml |
Physical Characteristics of Bromate ion (BrO3– )
It is a crystalline solid
The color of the bromate ion varies from colorless to slight color.
It can damage to skin and eyes.
Hazards of Bromate ion (BrO3– )
Bromate ion (BrO3– ) is hazardous to human health as:
It can cause eye and skin irritation.
It can damage the mucous membrane.
It can cause cancer if inhaled directly with water.
It directly attacks kidneys and causes toxicity and cancer as well.
Uses of Bromate ion (BrO3– )
It is used for the disinfection of the drinking water but in a certain quantity. If it exceeds a certain level it is fatal to health.
Conclusion
The article describes the Lewis structure of BrO3– and its importance in chemistry and molecular geometry. The steps to draw the Lewis structure of BrO3– have been discussed in the article. The molecular geometry of BrO3– is trigonal pyramidal and its asymmetrical in shape which makes it polar. Different factors can affect the polarity of the molecule or atom. BrO3-1 varies in color from colorless to slight color and can be hazardous to health because of its explosive and reactive nature. It is used for disinfection purposes but is very fatal for health if exposed beyond a certain limit.
FAQs
BrO3– is polar or non-polar? and Why?
The separation of electric charge that results in one negatively charged end and one positively charged end is known as polarity. Because of the difference in the electronegativity values of the involved atoms, this charge separation causes a net dipole moment on the overall molecule.
BrO3– is a polar molecule because of its asymmetric structure, which causes an unequal charge distribution around atoms, making it harder to cancel out the dipole along with five Br- O bonds, leading to a net dipole moment for it. As a result, BrO3– has a polar structure.
What is the molecular geometry of BrO3–?
Molecular geometry or molecular structure refers to the three-dimensional shape or arrangement of atoms in a molecule. Understanding a compound’s molecular structure can help to determine its polarity, reactivity, phase of matter, color, magnetism, and biological activity.
The geometry of BrO3-1 is trigonal pyramidal
What is the bond angle and shape of BrO3-1?
In BrO3-1 the bond angle is 104o because of the repulsion of the lone pairs. While the structure is trigonal pyramidal.
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