Isomerism is the phenomenon in which more than one compound has the same chemical formula but different chemical structures. Chemical compounds that have identical chemical formulas but differ in properties and the arrangement of atoms in the molecule are called isomers. Therefore, the compounds that exhibit isomerism are known as isomers. There are two primary types of isomerism, which can be further categorized into different subtypes. These primary types are Structural Isomerism and Stereoisomerism.
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When two molecules have exactly the same number of the same kinds of atoms, yet they have different chemical and physical properties, this is known as isomerism. Isomerism also takes into account timing and energy. Molecules are mobile entities that go through various rotating motions that change their shape, all of which require energy. As a result, specific molecules might be identical on one timeline or set of energy circumstances while being different or isomeric on another. Finally, an isomer must be an energy minimum; it must be found in a well of energy.
In this article, we will cover the topic (Isomerism). This topic falls under the broader category of (Some Basic Principles of Organic Chemistry), which is a crucial chapter in (Class 11 Chemistry).
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Compounds having the same molecular formula but different structures (manners in which atoms are linked) are classified as structural isomers. Some typical examples of different types of structural isomerism are given below:
It is the type of isomerism in which the compounds possessing same molecular formula differ in their properties due to the difference in their geomtery that is, due to the difference in the direction of attachment of same atoms or groups in their molecule. It is not shown by single bonded compounds like(C-C) due to free rotation.
Geometrical isomerism is shown by$[>\mathrm{C}=\mathrm{C}<],[>\mathrm{C}=\mathrm{N}-],\left[-\mathrm{N}=\mathrm{N}_{-}\right]$and cyclo alkanes.
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Cis
Trans
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It cannot show geometrical isomerism as one carbon atom has two similar species 'A'.
NCERT Chemistry Notes:
Q.1 The number of chiral centers in penicillin is:
(1) 3
(2) 4
(3) 5
(4) 6
Solution:
As we have learned
An asymmetric carbon atom (chiral carbon) is a carbon atom that is attached to four different types of atoms or groups of atoms.
As shown in the figure below, there are 3 chiral carbons in penicillin.
Therefore, option (1) is correct
Q.2 In the following structure, the double bonds are marked as I, II, III and IV
Geometrical isomerism is not possible at site (s) :
(1) III
(2) I
(3) I and II
(4) III and IV
Solution:
As we have learned
Geometrical isomerism is not possible at Site I as two identical methyl groups are attached to the same carbon bearing the double bond.
Hence, the answer is Option (2)
Q.3 Which of the following compounds will exhibit geometrical isomerism ?
(1) 1 - Phenyl - 2 - butene
(2) 3 - Phenyl - 1 - butene
(3) 2 - Phenyl - 1 - butene
(4) 1, 1 - Diphenyl - prop-1-ene
Solution:
As we have learned
Out of the given structures, only 1 - Phenyl - 2 - butene is capable of showing geometrical isomerism because it will show Cis–trans isomerism. Other structures have alkene at terminal carbon which does not show geometrical isomerism.
Hence, the correct answer is Option (1)
Isomerism is a key concept in chemistry that highlights the diversity and complexity of molecular structures. It occurs when compounds share the same molecular formula but differ in atom arrangement.
Isomerism arises from the fact that the atoms in a molecular formula can be organized in multiple ways to produce compounds with varied physical and chemical properties, known as isomers. Two main forms of isomerism are structural or constitutional isomerism, in which bonds between the atoms differ; and stereoisomerism or spatial isomerism, in which the bonds are the same but the relative positions of the atoms differ.
There are two common types of isomers. The Constitutional isomer is a molecule of different connections — like given simple bracelets where the arrangement of red and green beads is different. The second type are stereoisomers. For stereoisomers the connection is the same, but the components are oriented differently in space.
Isomerism is a disorder in which more than one compound has the same chemical formula but different chemical properties. Chemical compounds have the same chemical formulas but differ in the structure and arrangement of atoms in this molecule called isomers.
Enantiomers are chiral particles that are visual and cannot be elevated. Diastereomers are stereomer compounds with molecules that are invisible to each other's images and cannot be contradicted. There are no mirror images above each other.
You can distinguish them by their combination patterns and how they take up space with three. Identify the isomers of the structure (constitutional) with their integration patterns. The chemical atoms are the same but are connected in such a way that they form different functional isomerism groups
Functional isomerism occurs when substances have the same molecular formula but different functional groups. There are three functional group isomers of which you need to be aware: alcohols and ethers. aldehydes and ketones.
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Hello Gagan!
Sachin Rana's YouTube playlist (62 videos) or NS Sir's organic chemistry on the Mohit Tyagi Channel that you will follow for JEE Advanced depends on your needs and the constraints of time left for the examination.
Sachin Rana's Playlist:
NS Sir's Content:
Important factors:
Anyways, it's about finding the right balance between depth and timeliness. Whichever you do, practice regularly and take mock tests for how much you've improved.
Thankyou!!
Hello aspirant,
Here's a breakdown of your options and factors to consider:
Option 1: Continue with Sachin Rana's videos
Advantages:
Disadvantages:
Option 2: Switch to NS sir's lectures
Advantages:
Disadvantages:
Decision-Making Factors:
Recommendation:
Ultimately, the decision should be based on your individual preferences, learning style, and time constraints. It might be helpful to watch a few lectures from both teachers to see which one aligns better with your learning needs.
Additional Tips:
I hope this guidance helps you make an informed decision!
Completing organic chemistry (OC) from the Samarpan batch of MKA Sir on YouTube can be a good option for you, especially if you have already covered the basics of GOC and Isomerism. However, there are a few things to consider:
Overall, completing organic chemistry from the Samarpan batch of MKA Sir on YouTube is a feasible option for class 12th JEE aspirants. However, it is important to be realistic about your expectations and to supplement your learning with additional resources as needed.
I hope this information helps you.