Here we are going to discuss about the Lewis structure of NH3, structure of NH3, formal charge of NH3, dipole moment of NH3 ammonia, hybridisation of ammonia and bond angle of NH3 ammonia
Lewis structure of NH3 ammonia
Lewis structure of ammonia can be drawn by the following steps :
Determine the total number of valance electrons for the NH3 molecule. Nitrogen has 5 valance electrons. Each hydrogen has 1 valance electron. Therefore, for NH3 has a total of 5+3 * 1 = 8 valance electrons.
Place N in the centre and H at the corners. Now place the total 8 electrons in such a way that each hydrogen complete its duplet and nitrogen complete its octet.
First of all, share the bond pair between N and H. So total of six electrons are making 3 covalent bonds between nitrogen and hydrogen. Remaining 2 electrons on nitrogen atom acts as a lone pair.
Dipole moment of NH3 in structure of ammmonia
NH3 is a polar molecule which means it has a net dipole moment. Due to the difference in the electronegativity between nitrogen and hydrogen ammonia is a polar molecule. Nitrogen atom is more electronegative than hydrogen atom . Therefore it attracts the shared electron pair towards itself. This results in a partial negative charge on nitrogen atom and partial positive charge on hydrogen atom.
Dipole moment in structure of NH3
NH3 has a dipole moment due to the difference in electronnegativity between nitrogen and hydrogen atoms. 3 H atoms of NH3 are arranged around the central atom in a trigonal pyramidal shape. Geometry of NH3 molecule causes bond dipoles do not cancel out resulting in a net dipole moment.
To understand the complete topic go to the video structure of ammonia NH3
Hybridisation of NH3 in structure of ammmonia
We can determine the hybridisation of NH3 by using valance bond theory. It states that atomic orbitals overlap to form covalent bonds. In NH3 nitrogen is the central atom and has three single covalent bonds with three hydrogen atoms. Nitrogen has also one lone pair present on it. Electronic configuration of nitrogen in its ground state is 1s2 2s2 2p3 that forms 3 covalent bonds and 1 Lone pair on nitrogen atom. These oobitals will participate in hybridisation to form four equivalent hybridised orbitals.
Hybridisation of NH3 is Sp3 that is a combination of one 2s orbital and three 2p orbitals of nitrogen.
Bond angle in NH3 in structure of ammmonia
The bond angle of NH3 that is the angle between 2 H atoms and N atom is approximately 107 degrees. According to the geometry of NH3, 3 H atoms and one lone pair of electron is present around the central N atom in NH3 in a tetrahedral mannner. However lone pair is not shared with any other atom and takes more space than bonding pairs which leads to slight decrease of the bond angle. Decrease in bond angle from 109.5° to 107° occurs in ammonia due to lone pairs present on central nitrogen atom.
Formal charges in structure of NH3
To calculate the formal charges of the atoms in NH3,
We need to compare the number of valence electrons that each atom has in the molecule to the number of valence electrons it would have in its neutral state.
Therefore, the formal charge on nitrogen is:
FC(N) = Valence electrons in neutral atom – Non-bonding electrons – Bonding electrons/2
= 5 – 4 – 6/2
= 0
Therefore, the formal charge on each hydrogen atom is:
FC(H) = Valence electrons in neutral atom – Bonding electrons/2
= 1 – 1
= 0
Since all the formal charges on the atoms in NH3 are zero, this indicates that this Lewis structure is a good representation of the molecule. Because the electrons are evenly distributed among the atoms.
You can check the Mcqs of group 15 elements from P block elements in the link below ;
FAQs related to structure of NH3
Q: What is the formal charge on each atom of NH3?
A: The formal charges of all atoms in NH3 are zero. This indicates that the electrons are evenly distributed among the atoms.
Q: What is the hybridisation of NH3?
A: The hybridisation of NH3 is sp3. This hybridisation allows for the tetrahedral arrangement of the four electron pairs around the nitrogen atom.
Q: What is the dipole moment of NH3?
A: The dipole moment of NH3 is nearly 1.47 Debye. This dipole moment is relatively large and indicates a strong polarity in the molecule.
Q: What is the Lewis structure of NH3?
A: The Lewis structure of NH3 shows that the molecule has a trigonal pyramidal shape. NH3 molecule has nitrogen atom present at the centre bonded to three H atoms and one lone pair.
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