{"id":12624,"date":"2026-06-01T10:07:58","date_gmt":"2026-06-01T10:07:58","guid":{"rendered":"https:\/\/www.vedprep.com\/exams\/?p=12624"},"modified":"2026-06-01T10:15:08","modified_gmt":"2026-06-01T10:15:08","slug":"molecular-orbital-theory-2","status":"publish","type":"post","link":"https:\/\/www.vedprep.com\/exams\/iit-jam\/molecular-orbital-theory-2\/","title":{"rendered":"Molecular Orbital Theory (Diatomic molecules): IIT JAM 2027"},"content":{"rendered":"<p><strong>Molecular Orbital Theory<\/strong> (Diatomic molecules) For IIT JAM is a fundamental concept in chemistry that explains the electronic structure of diatomic molecules. It helps students understand the bonding and antibonding molecular orbitals, electron configurations, and molecular properties, which is essential for mastering <strong>Molecular Orbital Theory<\/strong> (Diatomic molecules) For IIT JAM.<\/p>\n<h2><strong>Syllabus and Key Textbooks: IIT JAM Chemistry Syllabus\u00a0<\/strong><\/h2>\n<p data-path-to-node=\"1\">Preparing for the<a href=\"https:\/\/jam2026.iitb.ac.in\/files\/syllabus_CY.pdf\" rel=\"nofollow noopener\" target=\"_blank\"><strong> IIT JAM<\/strong> <\/a>is a massive undertaking, and Unit 1.1 is where the real fun begins. <strong>Molecular Orbital Theory<\/strong> (MOT) for diatomic molecules isn&#8217;t just another topic to cross off your checklist; it&#8217;s a heavyweight concept that frequently crosses over into the IIT JAM syllabus (Molecular Structure). Master this now, and you are essentially setting yourself up for future success too.<\/p>\n<p data-path-to-node=\"2\">When you want to dive deep without getting lost in the weeds, stay away from random internet threads and stick to the classics. Here are the textbooks that should be on your desk:<\/p>\n<ul data-path-to-node=\"3\">\n<li>\n<p data-path-to-node=\"3,0,0\"><b data-path-to-node=\"3,0,0\" data-index-in-node=\"0\">Atkins, Physical Chemistry (10th edition):<\/b> It unpacks quantum principles and molecular structure with excellent clarity, helping you build a solid mental framework.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"3,1,0\"><b data-path-to-node=\"3,1,0\" data-index-in-node=\"0\">Levine, Physical Chemistry (6th edition):<\/b> If you want a thorough, step-by-step treatment of how atomic orbitals blend together, Levine is your best bet.<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"4\">These books give you the exact mathematical and conceptual grounding you need to crush those tricky multiple-choice questions (MCQs) and multiple-select questions (MSQs) from <strong>Molecular Orbital Theory<\/strong>.<\/p>\n<h2 data-path-to-node=\"6\"><strong>Molecular Orbital Theory: An Introduction<\/strong><\/h2>\n<p data-path-to-node=\"7\">Think back to school when we learned about Lewis structures and Valence Bond Theory. They were great for a start, but they fail to explain why an oxygen molecule sticks to a magnet. That is where <strong>Molecular Orbital Theory<\/strong> comes to the rescue.<\/p>\n<p data-path-to-node=\"8\">The core idea is simple: when atoms come close to form a molecule, their individual atomic orbitals lose their identity. Instead, they merge into a collective set of molecular orbitals that belong to the whole molecule.<\/p>\n<p data-path-to-node=\"9\">To visualize this, imagine two friends moving into a shared apartment. They don&#8217;t just stay confined to their old rooms; they now share the entire space. When atomic orbitals combine, they split into two main types:<\/p>\n<ol start=\"1\" data-path-to-node=\"10\">\n<li>\n<p data-path-to-node=\"10,0,0\"><b data-path-to-node=\"10,0,0\" data-index-in-node=\"0\">Bonding Molecular Orbitals:<\/b> Lower in energy, highly stable, and where electrons love to hang out because they pull the nuclei together.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"10,1,0\"><b data-path-to-node=\"10,1,0\" data-index-in-node=\"0\">Antibonding Molecular Orbitals:<\/b> Higher in energy, unstable, and featuring a &#8220;node&#8221; (a place with zero electron density) between the nuclei that pushes them apart.<\/p>\n<\/li>\n<\/ol>\n<p data-path-to-node=\"11\">By filling these orbitals with electrons according to the same old rules you already know (Aufbau, Pauli, and Hund\u2019s rule), you can figure out a molecule&#8217;s bond order, bond energy, and magnetic behavior to cover <strong>Molecular Orbital Theory<\/strong>.<\/p>\n<h2 data-path-to-node=\"13\"><strong>Types of Molecular Orbitals<\/strong><\/h2>\n<p data-path-to-node=\"14\">When you are sketching out these diagrams for your prep, you will run into two main kinds of bonds: Sigma (<span class=\"math-inline\" data-math=\"\\sigma\" data-index-in-node=\"107\">\u03c3<\/span>) and Pi (<span class=\"math-inline\" data-math=\"\\pi\" data-index-in-node=\"123\">\u03c0<\/span>).<\/p>\n<ul data-path-to-node=\"15\">\n<li>\n<p data-path-to-node=\"15,0,0\"><b data-path-to-node=\"15,0,0\" data-index-in-node=\"0\">Sigma (<span class=\"math-inline\" data-math=\"\\sigma\" data-index-in-node=\"7\">\u03c3<\/span>) Orbitals:<\/b> These form from head-on overlapping. A bonding <span class=\"math-inline\" data-math=\"\\sigma\" data-index-in-node=\"72\">\u03c3<\/span>\u00a0orbital is perfectly symmetrical around the bond axis. Flip it to an antibonding \u03c3<span class=\"math-inline\" data-math=\"\\sigma^*\" data-index-in-node=\"160\">*<\/span>\u00a0orbital, and you get a glaring nodal plane right between the atoms, which destabilizes the bond.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"15,1,0\"><b data-path-to-node=\"15,1,0\" data-index-in-node=\"0\">Pi (<span class=\"math-inline\" data-math=\"\\pi\" data-index-in-node=\"4\">\u03c0<\/span>) Orbitals:<\/b> These happen when orbitals overlap sideways. A bonding <span class=\"math-inline\" data-math=\"\\pi\" data-index-in-node=\"74\">\u03c0<\/span>\u00a0orbital looks like two lobes of electron density above and below the bond axis. The antibonding \u03c0<span class=\"math-inline\" data-math=\"\\pi^*\" data-index-in-node=\"174\">*<\/span>\u00a0orbital introduces an extra node, cutting through the space where the atoms are trying to connect.<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"16\">Knowing how <span class=\"math-inline\" data-math=\"\\sigma\" data-index-in-node=\"12\">\u03c3<\/span>, <span class=\"math-inline\" data-math=\"\\pi\" data-index-in-node=\"20\">\u03c0<\/span>, \u03c3<span class=\"math-inline\" data-math=\"\\sigma^*\" data-index-in-node=\"25\">*<\/span>, and \u03c0<span class=\"math-inline\" data-math=\"\\pi^*\" data-index-in-node=\"39\">*<\/span>\u00a0orbitals form is your golden ticket to solving structural problems quickly during the exam.<\/p>\n<h2><strong>Worked Example: Applying Molecular Orbital Theory (Diatomic molecules) For IIT JAM to Diatomic Molecules<\/strong><\/h2>\n<p data-path-to-node=\"19\">Let&#8217;s do a quick walkthrough with a classic exam favorite: the nitrogen molecule (<span class=\"math-inline\" data-math=\"\\text{N}_2\" data-index-in-node=\"82\">N<sub>2<\/sub><\/span>).<\/p>\n<p data-path-to-node=\"20\">A single nitrogen atom has 7 electrons (<span class=\"math-inline\" data-math=\"\\text{1s}^2 \\text{2s}^2 \\text{2p}^3\" data-index-in-node=\"40\">1s<sup>2<\/sup> 2s<sup>2<\/sup> 2p<sup>3<\/sup><\/span>), meaning an <span class=\"math-inline\" data-math=\"\\text{N}_2\" data-index-in-node=\"89\">N<sub>2<\/sub><\/span> molecule has a total of 14 electrons to distribute. For molecules like nitrogen (where <span class=\"math-inline\" data-math=\"Z \\le 7\" data-index-in-node=\"187\">Z \u2264 7<\/span>), mixing of the <span class=\"math-inline\" data-math=\"2\\text{s}\" data-index-in-node=\"211\">2s<\/span> and <span class=\"math-inline\" data-math=\"2\\text{p}\" data-index-in-node=\"225\">2p<\/span> orbitals alters the usual energy ordering. The \u03c0<sub><span class=\"math-inline\" data-math=\"\\pi_{2\\text{p}}\" data-index-in-node=\"282\">2p<\/span><\/sub>\u00a0orbitals actually sit lower in energy than the \u03c3<sub><span class=\"math-inline\" data-math=\"\\sigma_{2\\text{p}_z}\" data-index-in-node=\"345\">2pz<\/span><\/sub>\u00a0orbital.<\/p>\n<p data-path-to-node=\"21\">The molecular orbital configuration looks like this:<\/p>\n<p data-path-to-node=\"21\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-20273 aligncenter\" src=\"https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/orbital-configuration-300x40.png\" alt=\"orbital configuration\" width=\"300\" height=\"40\" srcset=\"https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/orbital-configuration-300x40.png 300w, https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/orbital-configuration.png 503w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/p>\n<p data-path-to-node=\"21\">To calculate the bond order, we use a straightforward formula:<\/p>\n<p data-path-to-node=\"21\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-20274 aligncenter\" src=\"https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/straightforward-formula-300x80.png\" alt=\"straightforward formula\" width=\"300\" height=\"80\" srcset=\"https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/straightforward-formula-300x80.png 300w, https:\/\/www.vedprep.com\/exams\/wp-content\/uploads\/straightforward-formula.png 342w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/p>\n<table data-path-to-node=\"25\">\n<thead>\n<tr>\n<td><strong>Aspect<\/strong><\/td>\n<td><strong>Value \/ Formula<\/strong><\/td>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><span data-path-to-node=\"25,1,0,0\"><b data-path-to-node=\"25,1,0,0\" data-index-in-node=\"0\">Bonding Electrons (<span class=\"math-inline\" data-math=\"N_{\\text{b}}\" data-index-in-node=\"19\">N<sub>b<\/sub><\/span>)<\/b><\/span><\/td>\n<td><span data-path-to-node=\"25,1,1,0\">10<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"25,2,0,0\"><b data-path-to-node=\"25,2,0,0\" data-index-in-node=\"0\">Antibonding Electrons (<span class=\"math-inline\" data-math=\"N_{\\text{a}}\" data-index-in-node=\"23\">N<sub>a<\/sub><\/span>)<\/b><\/span><\/td>\n<td><span data-path-to-node=\"25,2,1,0\">4<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"25,3,0,0\"><b data-path-to-node=\"25,3,0,0\" data-index-in-node=\"0\">Calculation<\/b><\/span><\/td>\n<td><span data-path-to-node=\"25,3,1,0\"><span class=\"math-inline\" data-math=\"(10 - 4) \/ 2\" data-index-in-node=\"0\">(10 &#8211; 4) \/ 2<\/span><\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"25,4,0,0\"><b data-path-to-node=\"25,4,0,0\" data-index-in-node=\"0\">Final Bond Order<\/b><\/span><\/td>\n<td><span data-path-to-node=\"25,4,1,0\"><b data-path-to-node=\"25,4,1,0\" data-index-in-node=\"0\">3<\/b><\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>A bond order of 3 tells us that nitrogen has an incredibly strong triple bond. Because every single electron is paired up, <span class=\"math-inline\" data-math=\"\\text{N}_2\" data-index-in-node=\"123\">N<sub>2<\/sub><\/span> is diamagnetic. If you run into a question about <span class=\"math-inline\" data-math=\"\\text{O}_2\" data-index-in-node=\"183\">O<sub>2<\/sub><\/span> or <span class=\"math-inline\" data-math=\"\\text{F}_2\" data-index-in-node=\"197\">F<sub>2<\/sub><\/span>, remember that the energy ordering flips back because the <span class=\"math-inline\" data-math=\"\\text{s-p}\" data-index-in-node=\"266\">s-p<\/span>\u00a0mixing becomes negligible!<\/p>\n<h2 data-path-to-node=\"28\"><strong>Common Misconceptions<\/strong><\/h2>\n<p data-path-to-node=\"29\">A frequent trap that candidates fall into is assuming that a higher bond order automatically means a molecule is completely unreactive. While a high bond order gives a molecule great thermodynamic stability, kinetics can tell a different story depending on what it is reacting with.<\/p>\n<p data-path-to-node=\"30\">Another classic slip-up is forgetting to change the orbital energy sequence when moving from nitrogen to oxygen. Skipping that adjustment will completely mess up your magnetic property predictions, turning an easy mark into a silly mistake.<\/p>\n<h2 data-path-to-node=\"32\"><strong>Application: Molecular Orbital Theory in Chemistry Lab<\/strong><\/h2>\n<p data-path-to-node=\"33\">We don&#8217;t just study this to pass exams; it actually explains how real things work. Imagine a fictional scenario where a lab team wants to create a molecule that changes color when exposed to specific toxic gases. They cannot just mix random chemicals and hope for the best.<\/p>\n<p data-path-to-node=\"34\">Instead, researchers model the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO). By figuring out the exact energy gap between these two levels, scientists can engineer materials that absorb specific wavelengths of light or react with precise targets.<\/p>\n<p data-path-to-node=\"35\">While calculating these states exactly can get messy\u2014requiring tricks like the Born-Oppenheimer approximation to ignore nuclear jitter and focus strictly on electron paths\u2014the underlying concept remains pure <strong>Molecular Orbital Theory<\/strong>. It serves as the foundation for modern quantum chemistry, catalysis, and advanced materials science.<\/p>\n<h2 data-path-to-node=\"37\"><strong>Mastering Molecular Orbital Theory for IIT JAM<\/strong><\/h2>\n<p data-path-to-node=\"38\">If you want to secure a top rank, you need to be able to draw these MO diagrams in your sleep. The exam questions will test your grasp on how adding or removing an electron changes everything. For instance, they love asking whether <span class=\"math-inline\" data-math=\"\\text{O}_2^+\" data-index-in-node=\"232\">O<sub>2<\/sub><sup>+<\/sup><\/span> is more stable than <span class=\"math-inline\" data-math=\"\\text{O}_2\" data-index-in-node=\"265\">O<sub>2<\/sub><\/span>, or whether <span class=\"math-inline\" data-math=\"\\text{B}_2\" data-index-in-node=\"288\">B<sub>2<\/sub><\/span>\u00a0is paramagnetic.<\/p>\n<p data-path-to-node=\"39\">Here is a straightforward strategy to nail this topic:<\/p>\n<ol start=\"1\" data-path-to-node=\"40\">\n<li>\n<p data-path-to-node=\"40,0,0\"><b data-path-to-node=\"40,0,0\" data-index-in-node=\"0\">Master the Core Diagrams:<\/b> Practice the specific structural differences between homonuclear diatomics (like <span class=\"math-inline\" data-math=\"\\text{C}_2\" data-index-in-node=\"107\">C<sub>2<\/sub><\/span>, <span class=\"math-inline\" data-math=\"\\text{N}_2\" data-index-in-node=\"119\">N<sub>2<\/sub><\/span>, <span class=\"math-inline\" data-math=\"\\text{O}_2\" data-index-in-node=\"131\">O<sub>2<\/sub><\/span>) and heteronuclear diatomics (like <span class=\"math-inline\" data-math=\"\\text{CO}\" data-index-in-node=\"177\">CO<\/span> and <span class=\"math-inline\" data-math=\"\\text{NO}\" data-index-in-node=\"191\">NO<\/span>).<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"40,1,0\"><b data-path-to-node=\"40,1,0\" data-index-in-node=\"0\">Link Bond Order to Properties:<\/b> Remember that a higher bond order means a shorter bond length and higher bond dissociation energy.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"40,2,0\"><b data-path-to-node=\"40,2,0\" data-index-in-node=\"0\">Spot Magnetism Instantly:<\/b> Look for unpaired electrons. If you see one, it&#8217;s paramagnetic; if everything is paired, it&#8217;s diamagnetic.<\/p>\n<\/li>\n<\/ol>\n<p data-path-to-node=\"41\">We at <a href=\"https:\/\/www.vedprep.com\/online-courses\/iit-jam\"><strong>VedPrep<\/strong> <\/a>understand that staring at dry, theoretical text can get overwhelming. Mixing your self-study routine with targeted problem-solving sessions is the best way to make these concepts stick.<\/p>\n<h2 data-path-to-node=\"49\"><strong>Real-World Applications of Molecular Orbital Theory<\/strong><\/h2>\n<p data-path-to-node=\"50\">The power of this theory goes far beyond simple textbook molecules. If you look at modern technology like the screen on your smartphone, you are looking at <strong>Molecular Orbital Theory<\/strong> in action.<\/p>\n<p data-path-to-node=\"51\">Organic Light-Emitting Diodes (OLEDs) and solar cells rely on conjugated organic molecules where electrons hop between different molecular orbitals. By tuning the HOMO-LUMO gap using computational methods like Density Functional Theory, scientists design organic materials that emit brilliant colors or capture sunlight with high efficiency.<\/p>\n<p data-path-to-node=\"52\">Every time you see a crisp, bright display on a phone, remember that it&#8217;s just a practical application of electrons moving through carefully engineered molecular orbitals.<\/p>\n<h2 data-path-to-node=\"52\"><strong>Final Thoughts<\/strong><\/h2>\n<p data-path-to-node=\"52\">Mastering <strong>molecular orbital theory<\/strong> isn\u2019t just about memorizing configurations or blindly applying formulas to score high on the IIT JAM\u2014it\u2019s about training your mind to look at chemical bonding through a realistic, quantum mechanical lens. When you transition from simply drawing Lewis structures to actively visualizing electron density clouds, tricky exam questions on bond parameters and magnetic behavior become second nature.<\/p>\n<p data-path-to-node=\"52\">To learn more from our expert faculty, watch our YouTube video:<\/p>\n<p class=\"responsive-video-wrap clr\"><iframe title=\"Molecular Orbital Theory Inorganic Chemistry | Molecular orbital diagram | CSIRNET\/GATE\/IITJAM\/TIFR\" width=\"1200\" height=\"675\" src=\"https:\/\/www.youtube.com\/embed\/UxE1iA46Nu8?list=PLdZcCa6mtW23WX31mHbmyi2vOvNGKZM-O\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<section>\n<h2><strong>Frequently Asked Questions<\/strong><\/h2>\n<style>#sp-ea-20277 .spcollapsing { height: 0; overflow: hidden; transition-property: height;transition-duration: 300ms;}#sp-ea-20277.sp-easy-accordion>.sp-ea-single {margin-bottom: 10px; border: 1px solid #e2e2e2; }#sp-ea-20277.sp-easy-accordion>.sp-ea-single>.ea-header a {color: #444;}#sp-ea-20277.sp-easy-accordion>.sp-ea-single>.sp-collapse>.ea-body {background: #fff; color: #444;}#sp-ea-20277.sp-easy-accordion>.sp-ea-single {background: #eee;}#sp-ea-20277.sp-easy-accordion>.sp-ea-single>.ea-header a .ea-expand-icon { float: left; color: #444;font-size: 16px;}<\/style><div id=\"sp_easy_accordion-1780307777\">\n<div id=\"sp-ea-20277\" class=\"sp-ea-one sp-easy-accordion\" data-ea-active=\"ea-click\" data-ea-mode=\"vertical\" data-preloader=\"\" data-scroll-active-item=\"\" data-offset-to-scroll=\"0\">\n\n<!-- Start accordion card div. -->\n<div class=\"ea-card ea-expand sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202770\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202770\" aria-controls=\"collapse202770\" href=\"#\"  aria-expanded=\"true\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-minus\"><\/i> What is the fundamental difference between Valence Bond Theory (VBT) and Molecular Orbital Theory (MOT)?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse collapsed show\" id=\"collapse202770\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202770\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>VBT assumes that electrons belong to individual atoms and localize between two bonding nuclei during orbital overlap. MOT, on the other hand, treats the entire molecule as a single unit, where atomic orbitals merge completely to form molecular orbitals that delocalize electrons over the whole molecule.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202771\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202771\" aria-controls=\"collapse202771\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> Why do bonding molecular orbitals have lower energy than the parent atomic orbitals?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202771\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202771\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Bonding molecular orbitals (<span class=\"math-inline\" data-math=\"\\text{BMOs}\" data-index-in-node=\"117\">BMOs<\/span>) are formed by the constructive interference (in-phase combination) of atomic orbital wave functions. This increases the electron density between the two nuclei, shielding them from mutual repulsion and resulting in a more stable, lower-energy state.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202772\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202772\" aria-controls=\"collapse202772\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> What exactly happens to the electron density in an antibonding molecular orbital?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202772\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202772\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Antibonding molecular orbitals (<span class=\"math-inline\" data-math=\"\\text{ABMOs}\" data-index-in-node=\"118\">ABMOs<\/span>) are the result of destructive interference (out-of-phase combination). The wave functions cancel each other out between the nuclei, creating a region of zero electron density known as a nodal plane. Because the nuclei are exposed to each other, repulsive forces increase, driving the energy up.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202773\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202773\" aria-controls=\"collapse202773\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> What are non-bonding molecular orbitals, and when do they form?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202773\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202773\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Non-bonding molecular orbitals form when atomic orbitals have incompatible symmetries or are too far apart in energy to interact. The electrons in these orbitals do not contribute to or detract from the bond strength, so their energy remains identical to that of the parent atomic orbitals.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202774\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202774\" aria-controls=\"collapse202774\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> How do you construct a molecular orbital diagram for a heteronuclear diatomic molecule like CO or NO?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202774\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202774\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>The basic principles remain the same, but the atomic orbitals of the more electronegative atom (like Oxygen) sit lower in energy than those of the less electronegative atom (like Carbon or Nitrogen). This asymmetry means the bonding molecular orbitals look and act more like the electronegative atom's orbitals, while the antibonding molecular orbitals align closer to the electropositive atom.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202775\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202775\" aria-controls=\"collapse202775\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> Why does the CO molecule have an anomalous bond order calculation?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202775\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202775\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p><span class=\"math-inline\" data-math=\"\\text{CO}\" data-index-in-node=\"78\">CO<\/span>\u00a0exhibits significant <span class=\"math-inline\" data-math=\"\\text{s-p}\" data-index-in-node=\"109\">s-p<\/span> mixing and severe asymmetry. Electrons are removed from a weakly antibonding or non-bonding orbital (\u03c3<span class=\"math-inline\" data-math=\"\\sigma_{2\\text{s}}^*\" data-index-in-node=\"221\"><sub>2s<\/sub><sup>*<\/sup><\/span>) when it ionizes to form <span class=\"math-inline\" data-math=\"\\text{CO}^+\" data-index-in-node=\"267\">CO<sup>+<\/sup><\/span>. Consequently, while <span class=\"math-inline\" data-math=\"\\text{CO}\" data-index-in-node=\"300\">CO<\/span> has a bond order of 3, <span class=\"math-inline\" data-math=\"\\text{CO}^+\" data-index-in-node=\"333\">CO<sup>+<\/sup><\/span>\u00a0surprisingly increases its bond order to 3.5, making it a favorite trick question in the IIT JAM exam.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202776\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202776\" aria-controls=\"collapse202776\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> Can a molecule have a fractional bond order, and what does it mean?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202776\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202776\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Yes, fractional bond orders like 0.5, 1.5, or 2.5 are perfectly normal in MOT. They indicate that the molecule contains an odd number of electrons distributed across its bonding or antibonding fields. While stable enough to exist under specific laboratory conditions (like <span class=\"math-inline\" data-math=\"\\text{H}_2^+\" data-index-in-node=\"346\">H<sub>2<\/sub><sup>+<\/sup><\/span>\u00a0or <span class=\"math-inline\" data-math=\"\\text{O}_2^-\" data-index-in-node=\"362\">O<sub>2<\/sub><sup>-<\/sup><\/span>), they are generally more reactive than molecules with whole-number bond orders.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202777\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202777\" aria-controls=\"collapse202777\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> If two molecular species have the exact same bond order, how do you determine which one is more stable?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202777\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202777\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Look closely at the distribution of the electrons. The species with more electrons sitting in <b data-path-to-node=\"21\" data-index-in-node=\"203\">antibonding orbitals<\/b> will be less stable because antibonding electrons destabilize a molecule more than bonding electrons stabilize it.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202778\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202778\" aria-controls=\"collapse202778\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> How do you quickly determine if a diatomic species is diamagnetic or paramagnetic?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202778\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202778\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Count the total number of valence electrons. If the total electron count is odd (like <span class=\"math-inline\" data-math=\"\\text{NO}\" data-index-in-node=\"174\">NO<\/span>\u00a0with 15 electrons), it is automatically paramagnetic. If the count is even, it is usually diamagnetic\u2014<b data-path-to-node=\"22\" data-index-in-node=\"286\">except<\/b> for species with 10 or 16 total electrons (like <span class=\"math-inline\" data-math=\"\\text{B}_2\" data-index-in-node=\"341\">B<sub>2<\/sub><\/span> and <span class=\"math-inline\" data-math=\"\\text{O}_2\" data-index-in-node=\"356\">O<sub>2<\/sub><\/span>), which are paramagnetic due to degenerate <span class=\"math-inline\" data-math=\"\\pi\" data-index-in-node=\"410\">\u03c0<\/span>\u00a0or \u03c0<span class=\"math-inline\" data-math=\"\\pi^*\" data-index-in-node=\"417\">*<\/span>\u00a0orbital structures.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-202779\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse202779\" aria-controls=\"collapse202779\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> Why is the Born-Oppenheimer approximation essential for calculating molecular orbitals?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse202779\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-202779\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Nuclei are thousands of times heavier than electrons, meaning they move at a snail's pace by comparison. The Born-Oppenheimer approximation allows quantum chemists to treat the nuclei as fixed points while focusing entirely on calculating the rapid motion of the electrons, making highly complex molecular wave equations solvable.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-2027710\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse2027710\" aria-controls=\"collapse2027710\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> What does the term \"LCAO\" mean in the context of MOT?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse2027710\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-2027710\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>LCAO stands for <b data-path-to-node=\"35\" data-index-in-node=\"75\">Linear Combination of Atomic Orbitals<\/b>. It is the mathematical method used to construct molecular orbitals by adding or subtracting the wave functions (<span class=\"math-inline\" data-math=\"\\psi\" data-index-in-node=\"226\">\u03c8<\/span>) of individual atomic orbitals.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<!-- Start accordion card div. -->\n<div class=\"ea-card  sp-ea-single\">\n\t<!-- Start accordion header. -->\n\t<h3 class=\"ea-header\">\n\t\t<!-- Add anchor tag for header. -->\n\t\t<a class=\"collapsed\" id=\"ea-header-2027711\" role=\"button\" data-sptoggle=\"spcollapse\" data-sptarget=\"#collapse2027711\" aria-controls=\"collapse2027711\" href=\"#\"  aria-expanded=\"false\" tabindex=\"0\">\n\t\t<i aria-hidden=\"true\" role=\"presentation\" class=\"ea-expand-icon eap-icon-ea-expand-plus\"><\/i> Can Molecular Orbital Theory be applied to polyatomic molecules?\t\t<\/a> <!-- Close anchor tag for header. -->\n\t<\/h3>\t<!-- Close header tag. -->\n\t<!-- Start collapsible content div. -->\n\t<div class=\"sp-collapse spcollapse \" id=\"collapse2027711\" data-parent=\"#sp-ea-20277\" role=\"region\" aria-labelledby=\"ea-header-2027711\">  <!-- Content div. -->\n\t\t<div class=\"ea-body\">\n\t\t<p>Absolutely, but it gets complicated fast. Instead of simple diatomic diagrams, polyatomic MOT requires group theory and advanced symmetry principles to map out how orbitals stretch across three or more atoms. For your IIT JAM prep, focusing tightly on homonuclear and heteronuclear diatomics will cover the vast majority of your test questions.<\/p>\n\t\t<\/div> <!-- Close content div. -->\n\t<\/div> <!-- Close collapse div. -->\n<\/div> <!-- Close card div. -->\n<\/div>\n<\/div>\n\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Our guide covers the electronic structure of diatomic molecules, bonding and antibonding molecular orbitals, electron configurations, and molecular properties. It&#8217;s essential for mastering Molecular Orbital Theory (Diatomic molecules) For IIT JAM. Our guide is designed to help students prepare for CSIR NET, IIT JAM, and GATE exams.<\/p>\n","protected":false},"author":11,"featured_media":12623,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":"","rank_math_seo_score":87},"categories":[23],"tags":[2923,7559,7560,7562,7561,2922],"class_list":["post-12624","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-iit-jam","tag-competitive-exams","tag-molecular-orbital-theory-diatomic-molecules-for-iit-jam","tag-molecular-orbital-theory-diatomic-molecules-for-iit-jam-notes","tag-molecular-orbital-theory-diatomic-molecules-for-iit-jam-practice","tag-molecular-orbital-theory-diatomic-molecules-for-iit-jam-questions","tag-vedprep","entry","has-media"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/posts\/12624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/comments?post=12624"}],"version-history":[{"count":5,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/posts\/12624\/revisions"}],"predecessor-version":[{"id":20284,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/posts\/12624\/revisions\/20284"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/media\/12623"}],"wp:attachment":[{"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/media?parent=12624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/categories?post=12624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vedprep.com\/exams\/wp-json\/wp\/v2\/tags?post=12624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}