Home > Bond Parameters: Order, Resonance, Resonance Hybrid

Bond Parameters: Order, Resonance, Resonance Hybrid - (Concept)

Bond Order

Bond order is defined as the number of bonds between the two atoms in a molecule. For example, in H-H or H₂ molecule, there is only a single bond present thus its bond order is 1. Further, in O=O or O₂, the bond order is 2 as it has 2 bonds between the oxygen atoms.

Resonance

The nitrite anion can have two possible structures with the atoms in the same positions. The electrons involved in the N–O double bond, however, are in different positions as shown below.

If nitrite ions do indeed contain a single and a double bond, we would expect for the two bond lengths to be different. A double bond between two atoms is shorter than a single bond between the same two atoms. Experiments show, however, that both N–O bonds in NO²⁻ have the same strength and length, and are identical in all other properties.

It is not possible to write a single Lewis structure for NO²⁻ in which nitrogen has an octet and both bonds are equivalent. Instead, we use the concept of resonance: if two or more Lewis structures with the same arrangement of atoms can be written for a molecule or ion, the actual distribution of electrons is an average of that shown by the various Lewis structures. The actual distribution of electrons in each of the nitrogen-oxygen bonds in NO²⁻ is the average of a double bond and a single bond. We call the individual Lewis structures resonance forms. The actual electronic structure of the molecule is called a resonance hybrid of the individual resonance forms. A double-headed arrow between Lewis structures indicates that they are resonance forms. Thus, the electronic structure of the NO²⁻ ion is shown as:

Resonance Hybrid
It is the average of the resonance forms shown by the individual Lewis structures or canonical structures.

Concepts List

« Previous Concept List Next »

Exam	Chapter
JEE MAIN	Chemical Bonding and Molecular Structure

A.	$\mathrm{O}=\mathrm{C}=\mathrm{O}$
B.	${ }^{-} \mathrm{O}-\mathrm{C} \equiv \mathrm{O}^{+}$
C.	$\mathrm{O}^{+}-\mathrm{C} \equiv \mathrm{O}^{-}$
D.	$\mathrm{O}^{+} \equiv \mathrm{C}-\mathrm{O}^{-}$

A.	3 and 2
B.	3 and 2.5
C.	3 and 1.3
D.	3 and 3.5

A.	The contributing structures must have the same number of unpaired electrons.
B.	The contributing structures should be so written that unlike charges reside on atoms that are far apart.
C.	The contributing structures should have similar energies.
D.	The positive charge should be present on the electropositive element and the negative charge on electronegative element.

A.	3, paramagnetic
B.	$2\frac{1}{2}$ , diamagnetic
C.	3, diamagnetic
D.	$2\frac{1}{2}$ , paramagnetic

A.	$O=C=O$
B.	${ }^{-} O-C \equiv O^{+}$
C.	${ }^{+} O\equiv C-O^{-}$
D.	$O\equiv C=O$

A.	Resonance structures should have equal energy
B.	In resonance structures, the constituent atoms should be in the same position
C.	In resonance structures, there should not be the same number of electron pairs
D.	Resonance structures should differ only in the location of electrons around the constituent atoms

A.	$\mathrm{SO}_{3}$
B.	$\mathrm{O}_{2}$
C.	$\mathrm{SO}_{2}$
D.	$\mathrm{CO}_{3}^{2-}$

A.	If both assertion and reason are true and reason is correct explanation of assertion
B.	If both assertion and reason are true but reason is not correct explanation of assertion
C.	If assertion is true but reason is false
D.	If both assertion and reason are false

A.	(i) and (ii)
B.	(iii) and (iv)
C.	(ii) and (iii)
D.	None of above

A.	$\mathrm{O}_2$
B.	$\mathrm{O}_2{ }^{+}$
C.	$\mathrm{O}_2^{-}$
D.	all of the above

A.	$\mathrm{O}_2^{-}<\mathrm{O}_2<\mathrm{O}_2^{+}<\mathrm{O}_2^{2-}$
B.	$\mathrm{O}_2^{-}<\mathrm{O}_2<\mathrm{O}_2^{+}<\mathrm{O}_2^{2-}$
C.	$\mathrm{O}_2^{2-}<\mathrm{O}_2^{-}<\mathrm{O}_2<\mathrm{O}_2^{+}$
D.	$\mathrm{O}_2^{+}<\mathrm{O}_2<\mathrm{O}_2^{-}<\mathrm{O}_2^{2-}$.

A.	Both reaction (I) and (II)
B.	Only reaction (I)
C.	Only reaction (II)
D.	Neither reaction (I) nor reaction (II)

A.	CO and $\mathrm{O}_2{ }^{2-}$
B.	$\mathrm{O}_2^{-}$and CO
C.	$\mathrm{O}_2{ }^{2-}$ and $\mathrm{B}_2$
D.	CO and $\mathrm{N}_2^{+}$

A.	(i) and (iii)
B.	(ii) and (iv)
C.	(iii) and (iv)
D.	None of above

A.	Hydrogen
B.	Fluorine
C.	Helium
D.	Iodine

A.	CO₃^-2
B.	C₆H₆
C.	So₃^-2
D.	C₃H₆

A.	$N_2$
B.	$P_4$
C.	$As_4$
D.	$Sb_4$

A.	$\mathrm{O}_2$
B.	$F_2$
C.	$\mathrm{O}_2^{+}$
D.	$F_2^{-}$

A.	NaCl being an ionic compound is a good conductor of electricity in the solid state.
B.	In canonical structures there is a difference in the arrangement of atoms.
C.	Hybrid orbitals form stronger bonds than pure orbitals.
D.	VSEPR Theory can explain the square planar geometry of $X e F_4$

A.	Electronic orbitals of carbon atom are hybridised.
B.	The $C=O$ bond is weaker than the $C-O$ bond
C.	The anion HCOO^- has two resonating structures.
D.	The anion is obtained by removal of a proton from the acid molecule

A.	All these structures are in dynamic equilibrium with each other.
B.	It is possible to identify each structure individually by some physical or chemical method.
C.	Each structure exists for equal amount of time.
D.	CO₃^2- has a single structure i.e., resonance hybrid of the above three structures.

A.	II $>$ III $>$ I
B.	III $>$ II $>$ I
C.	I $>$ II $>$ III
D.	II $>$ I $>$ III

A.	$C N^{-}$
B.	$\mathrm{NO}^{+}$
C.	$\mathrm{O}_2^{-}$
D.	$\mathrm{O}_2{ }^{2-}$

A.	$O_2^{-}>O_2>O_2^{+}$
B.	$\mathrm{O}_2^{-}<\mathrm{O}_2<\mathrm{O}_2^{+}$
C.	$\mathrm{O}_2^{-}>\mathrm{O}_2<\mathrm{O}_2^{+}$
D.	$O_2^{-}<O_2>O_2^{+}$

Exams

Colleges

Predictors

Resources

Quick links

Quick Links

Exams

Colleges

Resources

Colleges

Resources

Exams

Exams

Colleges

Resources

Diploma Colleges

Other Exams

Exams

Resources

Upcoming Events

Exams

Top Schools

Products & Resources

NCERT Study Material

Top Countries

Resources

Exams

Colleges

Exams

Colleges

Upcoming Events

Resources

Exams

Colleges & Courses

Predictors

Resources

Law Preparation

MBA Preparation

Engineering Preparation

Medical Preparation

Top Streams

Specializations

Resources

Top Providers

Exams

Colleges

Predictors

Resources

Resources

Exams

Colleges

Predictors & E-Books

Exams

Predictors & Articles

Colleges

Resources

Exams

Colleges

Resources

Top Courses & Careers

Colleges

Exams

Resources

Bond Parameters: Order, Resonance, Resonance Hybrid - (Concept)

Resonance

Ask your Query

Welcome Back :)

Register to post Answer

Welcome Back :)