How to draw NBr3 Lewis Structure? - Science Education and Tutorials

Q: What is the NBr3 Lewis structure?

NBr3 Lewis structure is dot representation

Q: What is the formal charge on the NBr3 Lewis structure?

Zero charges on the NBr3 molecular structure

The nitrogen tribromide chemical formula is NBr3. Drawing NBr3 Lewis Structure is very easy to by using the following method. Here in this post, we described step by step method to construct NBr3 Lewis Structure. The nitrogen and bromine elements come as members of the nitrogen and halogen family groups from the periodic table respectively. The valence electrons in nitrogen and bromine are five and seven respectively. The branch of nitrogen halogen compound chemistry is used to make chemicals reagents for organic chemical reactions.

Table of Contents

Key Points To Consider When Drawing The NBr3 Electron Dot Structure

A three-step approach for drawing the NBr3 Lewis structure can be used. The first step is to sketch the Lewis structure of the NBr3 molecule, to add valence electrons around the nitrogen atom; the second step is to add valence electrons to the three bromine atoms, and the final step is to combine the step1 and step2 to get the NBr3 Lewis Structure.

The NBr3 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the NBr3 molecule. The geometry of the NBr3 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose the NBr3 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the three N-Br single bonds (dipole moment properties of the NBr3 molecule). The nitrogen-bromine bonds in nitrogen tribromide(NBr3), for example, are polarised toward the more electronegative bromine in NBr3 molecule, and because both bonds have the same size and are located around three bromine terminals of the trigonal pyramidal with one lone pair (in total two electrons) on the nitrogen atom, their sum of dipole moment is nonzero due to the NBr3 molecule’s bond dipole moment and more electron polarity to the bromine atoms. Because each three N-Br bonds polarity not canceled each other in the NBr3 molecule due to the presence of one lone pair of electrons. The nitrogen tribromide(NBr3) molecule is classified as a polar molecule.

The molecule of nitrogen tribromide (with trigonal pyramidal molecular geometry) is tilted, the bond angles between nitrogen and bromine are 101.5 degrees. It has a difference in electronegativity values between nitrogen and bromine atoms, with central nitrogen’s pull being less than terminal bromine’s in the NBr3 molecule. But they do not cancel each other due to the asymmetrical trigonal pyramidal with one lone pair in the molecular geometry of the NBr3 molecule.

As a result, it has the nonzero dipole moment. The NBr3 molecule has a nonzero dipole moment due to an unequal charge distribution of negative and positive charges. But both nitrogen and bromine atoms fall on the nitrogen and halogen family groups in the periodic table respectively. The bromine atom is a more electronegative value than nitrogen in the NBr3 molecule. The NBr3 molecule has the net dipole moment of non-zero value in the ground state energy state.

NBr3 molecule has three N-Br single bonds. Its dipole moment in the ground state is totally different as compared with the excited state. If it absorbs light may be from visible or UV light. It undergoes pi to pi star and n to pi star transition from ground state energy level to excited state energy level. In the excited state energy level, the NBr3 molecule shows a definite dipole moment. But it is very dynamics.

Molecules can be classified as polar or nonpolar. The molecule polar behaves in a different manner as compared to nonpolar.

Overview: NBr3 Lewis Structure

The central atom is nitrogen, which is bordered on three terminals with bromine atoms( in trigonal pyramidal geometry), and one lone pair on the central nitrogen atom in the trigonal pyramidal molecular geometry. nitrogen has five outermost valence electrons, indicating that it possesses five electrons in its outermost shell, whereas bromine also has seven valence electrons in its outermost shell. To complete the octet of the nitrogen and bromine atoms requires three and one valence electrons on each of their outermost shell respectively.

Three bromine atoms establish covalent connections with the central nitrogen atom as a result, leaving the nitrogen atom with one lone pair. There is one lone pair of electrons on the nitrogen central atom that resists the bond pairs of the three N-Br bonds. According to VSEPR theory, the single N-Br bond pairs polarity lead the NBr3 molecule to take on the trigonal pyramidal geometry structure.

The NBr3 molecule’s three N-Br bonds are arranged in symmetrical polarity order around the trigonal pyramidal molecular geometry, giving rise to the NBr3 molecular shape. The NBr3 molecule has a trigonal pyramidal molecular geometry because there is an electrical repulsion between the lone pairs of electrons in nitrogen and three single bond pairs(N-Br) of the NBr3 molecule.

Lewis structure of NBr3 has dot electron representative structure. Valence electrons of atoms undergo orbitals mixing in the chemical reactions, giving new types of molecular species of NBr3. The molecule is nothing but a bundle of valence electrons from the atoms. But it is converted to bond pairs and lone pairs in the molecular structure.

Electronegative value Difference Calculation of NBr3 Molecule:

Nitrogen and bromine Electronegative difference in NBr3:

The nitrogen atom has an electronegativity of 2.19, while bromine has an electronegativity of 2.96 in the NBr3 molecule. The difference in electronegativity of nitrogen and bromine can be estimated using the method below.

The electronegative value difference between nitrogen and bromine in NBr3 molecule
Electronegativity value of nitrogen = 2.19
Electronegativity value of bromine= 2.96
Difference of electronegativity value between nitrogwen and bromine in NBr3 molecule = 2.96 – 2.19 = 0.77
Electronegativity difference between N-Br bond calculation of NBr3 molecule

The electronegative difference between nitrogen and bromine is greater than 0.5. This indicated the bond polarity moves near to polar nature. N-Br bond polarity in the NBr3 molecule is polar.

Because of this difference in electronegativity of nitrogen and bromine atoms, the NBr3 molecule’s N-Br bond becomes polar. The total net dipole moment of the NBr3 molecule is nonzero due to the noncancellation of the bond dipole moment in the trigonal pyramidal geometry. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of NBr3 is discussed in our previous post.

As a result, the N-Br bond’s dipole moment is high due to the polarization of the bonds and one lone pair of electrons on nitrogen, and all N-Br bonds’ dipoles are arranged in the asymmetrical NBr3 molecular geometry. The NBr3 molecule has a nonzero net dipole moment.

The electron dot structure of the NBr3 molecule is also known as the NBr3 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the NBr3 molecule’s bond formation. The outermost valence electrons of the NBr3 molecule must be understood while considering the Lewis structure of the molecule.

The nitrogen atom is the middle element in NBr3 molecular geometry, with five electrons in its outermost valence electron shell, whereas the bromine atom has seven electrons in its outermost valence electron shell. The bromine atom has seven valence electrons.

The NBr3 has a total of 26 valence electrons as a result of the foregoing above-said reasoning. With the core central nitrogen atom, the three terminals with three bromine atoms form covalent bonds, leaving the nitrogen atom with one lone pair in the middle of trigonal pyramidal geometry.

Because lone pairs on the terminal bromine atoms create interaction with N-Br bond pairs(but it is negligible in the ground state of the NBr3 molecule). The bond angle of the Br-N-Br bond in the trigonal pyramidal molecular geometry is approximately 101.5 degrees. This angle is less than the CH4 molecule bond angle. The N-Br bond length is 222pm(picometer).

To sketch the NBr3 Lewis structure by following these instructions:

Step-1: NBr3 Lewis dot Structure by counting valence electrons on the nitrogen atom

To calculate the valence electron of each atom in NBr3, look for its periodic group from the periodic table. The nitrogen and halogen group families, which are the 15th and 17th groups in the periodic table, are both made up of nitrogen and bromine atoms respectively. In their outermost shells, bromine and nitrogen have seven and five valence electrons respectively.

Calculate the total number of valence electrons in the NBr3 molecule’s outermost valence shell. The first step is to determine how many electrons are in the NBr3 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the NBr3 Lewis diagram. The NBr3 molecule’s core nitrogen atom can be represented as follows:

Total outermost valence shell electron of nitrogen atom in NBr3= 5
Total outermost valence shell electron of bromine atom in NBr3= 7
The NBr3 molecule has one central nitrogen and three bromine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for NBr3 Lewis structure( dot structure) = 5+3*7= 26 valence electrons in NBr3.
calculation of total valence electron of NBr3 molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of NBr3. We’ll choose the least electronegative value atom in the NBr3 molecule to place in the center of the NBr3 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

The first step is to put five valence electrons around the nitrogen atom as given in the figure.

Step-2: Lewis Structure of NBr3 for counting valence electrons around the terminal bromine atoms

As a result, nitrogen is the first atom in the periodic table’s nitrogen family group. Bromine is the third member of the halogen family. The electronegative value of the bromine atom is higher than that of the nitrogen atom in the NBr3 molecule. Furthermore, bromine has a seven electrons limit since nitrogen is the less electronegative element in the NBr3 molecule.

In the NBr3 Lewis structure diagram, the nitrogen atom can be the center atom of the molecule. As a result, central nitrogen in the NBr3 Lewis structure, with all three bromine atoms arranged in a trigonal pyramidal geometry.

Add valence electrons around the bromine atom, as given in the figure.

Step-3: Lewis dot Structure for NBr3 generated from step-1 and step-2

Connect the exterior and core central atom of the NBr3 molecule with three single N-Br bonds. In this stage, use three bromine atoms on the outside of the NBr3 molecule to the central nitrogen atom in the middle.

Count how many electrons from the outermost valence shell have been used in the NBr3 structure so far. Each N-Br single bond carries two electrons because each nitrogen atom is connected to three bromine atoms by three N-Br single bonds. Bond pairings of N-Br are what they’re called.

So, out of the total of 26 valence electrons available for the NBr3 Lewis structure, we used six electrons for the NBr3 molecule’s three N-Br single bonds. The NBr3 molecule has one lone pair of electrons in the central nitrogen atom.

Place the valence electrons in the N-Br bond pairs starting with the core nitrogen, three bromine atoms in the NBr3 molecule. In the NBr3 Lewis structure diagram, we always begin by introducing valence electrons from the central nitrogen atom(in step1). As a result, wrap around the central nitrogen atom’s bond pair valence electrons first (see figure for step1).

The nitrogen atom in the molecule gets only 8 electrons around its molecular structure. This central nitrogen atom is octet stable. But it has one lone pair. nitrogen is a brownish solid in nature. nitrogen catch fire in the exposure to air. But nitrogen is used in matchboxes and firecrackers.

Bromine(Br2) is in the gaseous liquid state at normal temperature and pressure. It is used as a brominating agent in the field of organic chemistry. It is a highly corrosive gaseous liquid. It is responsible for dry corrosion in the metal bodies. It is very reactive to bio-micro organisms.

nitrogen requires 8 electrons in its outermost valence shell to complete the molecular octet stability, six electrons bond pairs in three N-Br single bonds, and one lone pair in the central nitrogen atom. Then lone pair of electrons on the bromine atoms of the NBr3 molecule is placed in a trigonal pyramidal geometry. nitrogen already shares 8 electrons to the three N-Br single bonds. Then place the valence electron in the bromine atoms, it placed around seven electrons on each atom(step-2). 18 valence electrons were placed around three bromine atoms as lone pairs of electrons.

We’ve positioned 18 electrons around the three-terminal bromine atoms(step-3), which is represented by a dot, in the NBr3 molecular structure above. The nitrogen atom completes its molecular octet stability in the NBr3 molecule because it possesses six electrons in its (three N-Br single bonds) bond pairs with three bromine in the outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the NBr3 Lewis structure. three electron bond pairs are shown as dots in the NBr3 chemical structure, whereas three single bonds each contain two electrons. The outermost valence shell electrons of the NBr3 molecule(bond pairs) are six as a result of the calculation. The total valence electron in a nitrogen atom is 8.

So far, we’ve used 26 of the NBr3 Lewis structure’s total 26 outermost valence shell electrons. One lone pair of electrons on the nitrogen atom in the trigonal pyramidal geometry of the NBr3 molecule.

Complete the middle nitrogen atom stability and, if necessary, apply a covalent bond. The central nitrogen atom undergoes octet stability(due to three single bond pairs of electrons).

The core atom in the NBr3 Lewis structure is nitrogen, which is bonded to the three bromine atoms by single bonds (three N-Br). With the help of three single bonds, it already shares 8 electrons. As a result, the nitrogen follows the octet rule and has 8 electrons surrounding it on the three terminals of the NBr3 molecule’s trigonal pyramidal geometry.

How to calculate the formal charge on nitrogen and bromine atoms in NBr3 Lewis Structure?

Calculating formal charge on the nitrogen of NBr3 molecule:

The formal charge on the NBr3 molecule’s nitrogen central atom often corresponds to the actual charge on that nitrogen central atom. In the following computation, the formal charge will be calculated on the central nitrogen atom of the NBr3 Lewis dot structure.

To calculate the formal charge on the central nitrogen atom of the NBr3 molecule by using the following formula:
The formal charge on the nitrogen atom of NBr3 molecule= (V. E(P)– L.E(P) – 1/2(B.E))
V.E (P) = Valence electron in a nitrogen atom of NBr3 molecule
L.E(P) = Lone pairs of an electron in the nitrogen atom of the NBr3 molecule.
B.E = Bond pair electron in P atom of NBr3 molecule
calculation of formal charge on nitrogen atom in NBr3 molecule

The nitrogen core atom (three single bonds connected to three bromine atoms ) of the NBr3 molecule has five valence electrons, one lone pair of electrons(two electrons), and six bonding pairing valence electrons. Put these values for the nitrogen atom in the formula above.

Formal charge on nitrogen atom of NBr3 molecule = (5- 2-(6/2)) =0

In the Lewis structure of NBr3, the formal charge on the central nitrogen atom is zero.

Calculating formal charge on the bromine atom of NBr3 molecule:

The formal charge on the NBr3 molecule’s bromine terminal atoms often corresponds to the actual charge on that bromine terminal atoms. In the following computation, the formal charge will be calculated on the terminal bromine atom of the NBr3 Lewis dot structure.

To calculate the formal charge on the terminal bromine atom of the NBr3 molecule by using the following formula:
The formal charge on the bromine atom of NBr3 molecule= (V. E(Br)– L.E(Br) – 1/2(B.E))
V.E (Br) = Valence electron in a bromine atom of NBr3 molecule
L.E(Br) = Lone pairs of an electron in the bromine atom of the NBr3 molecule.
B.E = Bond pair electron in Br atom of NBr3 molecule
calculation of formal charge on bromine atom in NBr3 molecule

The bromine terminal atoms of the NBr3 molecule have seven valence electrons, three lone pairs of electrons(six electrons), and two bonding pairing valence electrons(single bond). Put these values for the bromine atom in the formula above.

Formal charge on bromine atom of NBr3 molecule = (7- 6-(2/2)) =0

In the Lewis structure of NBr3, the formal charge on the terminal bromine atom is zero.

Summary:

In this post, we discussed the method to construct the NBr3 Lewis structure. First, the valence electrons are placed around the nitrogen atom. Second, place the valence electron on the bromine atoms. Finally, when we combined the first and second steps. It gives NBr3 Lewis structure. Need to remember that, if you follow the above-said method, you can construct molecular dot structure very easily.