JEE Advanced Important Questions of Chemical Bonding and Molecular Structure
FAQs on JEE Advanced Chemical Bonding and Molecular Structure Important Questions
1. What are Lewis Symbols?
A Lewis symbol, which is constructed by representing every electron in the outermost energy level (orbit) of an atom or molecule with a ‘solid dot’ drawn around its symbol, is basically a simplified version of Bohr’s diagram that give us information about the elemental properties and reactions. In order to draw the lewis symbol for a molecule, the first thing to do is to draw the lewis symbol for each individual atom. Then, a ‘line’ joining two dots of the atoms needs to be drawn. This line denotes the bounded electrons, while the remaining dots represent the unbounded electrons.
2. What are the different types of chemical bonds?
Chemistry is basically the study of everything moving towards stability. A chemical bond forms when there is redistribution of electrons that make both participating elements move towards stability. This process of chemical bonding can take place in various ways depending upon the contributing elements, their properties as well external conditions. Some important types of chemical bonds that have been covered in the JEE syllabus are the Ionic bond (also called as an electrovalent bond), the covalent bond, the Hydrogen bond, and Polar covalent bond. You can check this page, where we’ve covered this topic in further detail.
3. What do you mean by Hybridization?
Hybridization is the process that involves the redistribution of energies of different atomic orbitals like s, p, d to give rise to new, ‘hybrid’ orbitals of equivalent energy. These hybrid orbitals have radically different shapes and properties from their constituent orbitals. It’s usually the atomic orbitals of the same energy level that take part in hybridization, but if they have equal energies, both fully filled and half-filled orbitals can also take part in hybridization. The different types of hybridization covered in the syllabus are sp,sp2, sp3, sp3d, and sp3d2. The percentage of s character in sp, sp2, and sp3 hybrid orbitals are 50%, 33.3%, and 25% respectively.
4. State and explain the Fajan’s rule.
Like we studied previously, there are different types of chemical bonds, the two most prominent ones being ionic and covalent bonds. In order to determine the type of bond that will be formed when two entities chemically interact, Kazimierz Fajan in 1923 formulated a theory which is today called Fajan’s rule. There are basically three rules which help us decide the type of bond that will be formed: the first rule speaks about the polarizing power of the cation, the second rule talks about the polarizability of the anion, and the third rule is a special case which tells us how to make the decision when the size of the participation ions are almost the same. We have a dedicated article just for the Fajan’s rule and we recommend students to go through it thoroughly.
5. What are the Postulates of the VSEPR’s theory?
The Valence Shell Electron Pair Repulsion (VSEPR) theory, which, as the name suggests, is based upon the repulsions between electron pairs which helps us determine the shape and geometry of the molecules. One of the few drawbacks of the Lewis theory was that it could not account for the shapes of the molecules, and provide reasons for why they had the geometry that they possessed. Thus, later on, Sidgwick and Powell provided the VSEPR theory that has the following postulates:
The VSEPR model is applicable to any structure where two or more resonance structures can represent a molecule.
Since the electron clouds are negatively charged, pairs of electrons which are present in the valence shell (outermost orbit) repel each other
They tend to minimize their repulsions and maximize their distance, by occupying appropriate positions
The shape of the chemically combined molecule depends upon the number of electron pairs prevalent in the valence shell, be it bounded or unbounded
The VSEPRs theory is extremely important both from the board and JEE point of view and thus students must thoroughly study and regularly revise it.
While solving all these questions, students must make sure they do so by creating an environment as close to an examination centre as possible. Taking frequent breaks, having snacks while solving the questions, referring to the solutions in the middle of the paper, using your phone, are some of the things the students must avoid at all costs since it disturbs the flow.
These questions have been designed by subject experts, keeping in mind the pattern and the difficulty level of the actual exam. After having completed the portion, students tend to focus only on solving papers based on the entire syllabus. However, solving such mini-papers that focus on sections of a subject, or even on individual chapters, can help them just as much. At Vedantu, you can find PDF documents that contain important questions to solve for every single chapter and students must make good use of them. Here’s wishing every aspirant the best of luck for their exam and educational career.