Organic Chemistry - Some Basic Principles and Techniques - Notes, Topics, Formula, Books, FAQs

This is the beginning of organic chemistry. In this chapter, you study the basic concepts like IUPAC nomenclature, isomerism, inductive effect, resonance effect. There are some reagents as well like nucleophile and electrophile that comes into picture only during the time of organic reactions. In isomerism, you will study the detailed analysis of isomerism and its various types. There are many organic compounds that have the same chemical formula but they differ in their physical properties. Besides, you will also study the benzene compounds and their substituents.

For this chapter, there are various real-life applications that we observe in our daily life. Some of them are mentioned below.

• For petrochemical products, most of the petrochemical products are hydrocarbons and their derivatives natural gas, kerosene, gasoline, etc.

• Resonance of molecules is the most stable structure of molecules and most stable structure is its middle form among all the resonance structures. This same phenomenon is used in swings.
  

Notes for Some Basic Principles of Organic Chemistry

In this section, you will study about the important topics of the chapter, overview, various important concepts and some important tips and guidelines for the preparation of the chapter at the best.

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Important Topics of Some Basic Principles of Organic Chemistry

• Tetravalence of carbon

• Structural representations of Organic Compounds

• Classification of Organic Compounds

• Nomenclature

• Isomerism

• Fundamental concepts in organic chemistry

Overview of the Chapter - Some Basic Principles of Organic Chemistry

In this chapter, you will study the basic concepts related to organic chemistry. First, you will learn the reason due to which carbon is able to form a large number of compounds. Besides, you will learn the rules to name these organic compounds, isomerism, resonance effect, inductive effect, etc. Besides, you will also learn important tips and the best book to prepare this in the most efficient way.

Tetravalence of Carbon

Tetravalency is one of the major reason due to which carbon is able to form many compounds. While the formation of a compound, carbon forms the hybrid orbitals and because of these hybrid orbitals, these molecules have a definite shape. Other than sigma bond, carbon forms π(pi) bond as well. In this type of bonding, the hybrid orbitals are not involved but they are formed by p-orbitals. In π bond, the parallel orientation of p-orbitals occurs on adjacent carbon atoms.

Structural representations of Organic Compounds

• Complete, condensed and Bond-line structural formulas:
  In 2-dimensional geometry, carbon compound structures are represented in three ways, i.e, complete structural formula, condensed structural formula and bond-line structural formula.

(i) Complete structural formula: In this structural representation, different atoms are shown as bonded with each other via single, double or triple bond as shown in the figure.

(ii) Condensed structural formula: In this type of representation, the bonds are not shown between the atoms but the identical groups attached to an atom are represented by a subscript as shown in the figure.

(iii) Bond-line structural formula: In this type of structural representation, carbon and hydrogen atoms are not shown only the dashes or bonds are shown. Other atoms or groups like chlorine, oxygen, etc. shown.

• Three-dimensional representation:
  The 3-D representation of carbon compounds is also possible on paper using ‘solid and dashed wedge’ formula. In this representation, the solid wedge is used to represent the bond that is out of paper and towards the observer and dash-wedge is used to represent the bond that is away from the observer. Other bonds in the compound are in the plane of the paper and are represented simply as dash lines.

Classification of Organic Compounds

On the basis of the structures, these organic compounds are classified as follows:

Nomenclature of substituted benzene compounds

For these compounds, the following rules are followed:

(i) If one substituent is present, then the name of the substituent is prefixed to the name of benzene.
(ii) If two substituents are present, then the numbering is done in such a way that these substituents get the lowest possible numbers.
(iii) If there are three or more substituents are present then naming is done bu identifying the substituent positions on the ring by following the lowest locant rule, then the direction of the numbering is done in such a way that the substituents get the lowest possible numbers. Some examples include:

Isomerism
When two or more compounds with the same chemical formula but different structures and properties are known as isomers and this phenomenon is known as isomerism.

Isomerism is of two types viz, structural isomerism and stereoisomerism

(i) Structural isomerism: In this phenomenon, compounds have the same chemical formula but they differ in their structures. It is further classified into various categories as follows:

• Chain isomerism: Two or more compounds with the same chemical formula but different structures are known as chain isomers. For example, C₅H₁₂ represent three different compounds as given below.
  
• Position isomerism: When two or more compounds have the same chemical formula but differ in the positions of their substituent atoms or functional groups are known as position isomers. For example, C₃H₈ represents two different alcohols.
  
• Functional group isomerism: When two or more compounds have the same chemical formula but differ in the functional groups attached are known as functional group.isomers. For example, C₃H₆O represents an aldehyde and a ketone.
  
• Metamerism: In this type of isomerism, compounds differ in the type of alkyl chain attached to a functional group.

(ii) Stereoisomerism: In this class of isomerism, compounds have the same chemical formula and the same sequence of covalent bonds but differ in the relative positions of their groups. It is further classified into two groups, i,e. geometrical isomerism and optical isomerism.

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Fundamental Concepts in Organic Chemistry

There are some important fundamental concepts that we need to understand carefully. These basic concepts are very useful for dealing with the organic reactions in later chapters.

• Nucleophiles: A nucleophile is a reagent that is either negatively charged or carry lone pair of electrons. These reagents attract the protons or positive charge towards themselves.
  
• Electrophiles: These are the reagents that are positively charged and require electrons to stabilize it.

• Inductive Effect: Inductive effect is the effect in which two different atoms of different electronegativities are bonded together. In this case, the bonded electrons are shifted towards the more electronegative atom and thus results in the polar covalent bond. When this shifting of electrons is towards the carbon then it is known as +I effect and when it is away from carbon, then it is -I effect. The relative inductive effect series based on the strength of -I effect is as follows:
  –NH3+ > –NO2 > –SO2R > –CN > –SO3H > –CHO > –CO > –COOH > -F > –COCl > -CONH2 > –Cl > –Br > –I > –OR > -OH > -NR2 > –NH2 > –C6H5 > –CH=CH2 > –H
• Resonance Effect: When the polarity of a bond is created due to the interaction of two ?-bonds or between a ?-bond and a lone pair of electrons on the adjacent atom. This effect is of two types:
  (i) Positive resonance effect(+R effect): In this effect, the electrons are shifted away from the substituted group attached to the conjugated system.
  (ii) Negative resonance effect(-R effect): In this effect, the electrons are shifted towards the substituted group attached to the conjugated system.
• Electromeric Effect: In this effect, the complete transfer of electrons takes place to one of the atoms which are directly bonded with the multiple bonds. This effect is only shown in the multiple bonds. It is temporary and becomes active only at the time of the reagent attack.
• Hyperconjugation: In this effect, delocalization of -electrons to the unsaturated system or unshared p-orbital takes place. This effect is permanent.

How to prepare for Some Basic Principles of Organic Chemistry

• This chapter is the beginning of organic chemistry. All the basic concepts and rules are covered in this chapter.
• For preparing this chapter, there is no need of any pre-requisite chapter. Thus prepare it freshly and actively.
• All these basic concepts and rules life resonance effect, isomerism, IUPAC, etc will be used in the later chapters of organic chemistry. Thus prepare this chapter carefully.
• In the nutshell, it can be said that although this chapter is not very long, it is a very simple and straightforward one. So always say a "Big YES" to this chapter.

NCERT Notes Subject Wise Link:

• NCERT notes for Class 11 Maths
• NCERT notes for Class 11 Physics
• NCERT notes for Class 11 Chemistry
• NCERT notes for Class 11 Biology

Prescribed Books

For this chapter, first, the NCERT book is best for initial level preparation as well as for board exams. Now, after this, if you want to prepare for competitive exams like JEE and NEET, then these are the best books for you - O.P Tandon. Meanwhile, in the preparation, you must continuously give the mock tests for the depth of knowledge. Our platform will help you to provide with the variety of questions for deeper knowledge with the help of videos, articles and mock tests.

NCERT Solutions Subject wise link:

• NCERT solutions for class 11 Physics.
• NCERT solutions for class 11 Chemistry.
• NCERT solutions for class 11 Mathematics.
• NCERT solutions for class 11 Biology.

NCERT Exemplar Solutions Subject wise link:

• NCERT exemplar solutions for class 11 Physics.
• NCERT exemplar solutions for class 11 Chemistry.
• NCERT exemplar solutions for class 11 Mathematics.
• NCERT exemplar solutions for class 11 Biology.