{"id":188097,"date":"2025-02-06T10:31:37","date_gmt":"2025-02-06T10:31:37","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=188097"},"modified":"2025-02-06T10:31:39","modified_gmt":"2025-02-06T10:31:39","slug":"list-the-symmetry-elements-of-the-following-molecules-and-name-the-point-groups-to-which-they-belong","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/06\/list-the-symmetry-elements-of-the-following-molecules-and-name-the-point-groups-to-which-they-belong\/","title":{"rendered":"List the symmetry elements of the following molecules and name the point groups to which they belong"},"content":{"rendered":"\n<p>a. List the symmetry elements of the following molecules and name the point groups to which they belong: (a) NO2, (b) N2O, (c) CHCl3, (d) CH2=CH2, (e) cis-CHBr=CHBr, (f) trans-CHCl=CHCl.<\/p>\n\n\n\n<p>b. List the symmetry elements of the following molecules and name the point groups to which they belong: (a) naphthalene, (b) anthracene, (c) the three dichlorobenzenes.<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">a. Symmetry Elements and Point Groups:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>NO2 (Nitrogen Dioxide)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> No mirror plane (\u03c3), no inversion center (i), and only a C\u2082 axis of symmetry (rotation about the bond axis).<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>C\u2082v<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> NO2 has a C\u2082 axis (rotation by 180\u00b0 around the N-O axis) and vertical mirror planes (\u03c3v) passing through the N and O atoms. It does not possess inversion symmetry.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>N2O (Nitrous Oxide)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u221e axis, inversion center (i).<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>D\u221eh<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> N2O has an infinite axis of symmetry (C\u221e), meaning it can rotate indefinitely with the same symmetry. Additionally, it possesses an inversion center at the nitrogen atom.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>CHCl3 (Chloroform)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2083 axis, \u03c3v mirror planes.<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>C\u2083v<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> Chloroform has a C\u2083 axis of symmetry (rotation by 120\u00b0 around the C-H axis) and three vertical mirror planes passing through the C atom and one of the Cl atoms.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>CH2=CH2 (Ethene)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2082 axis, \u03c3h mirror plane.<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>D\u2082h<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> Ethene has a C\u2082 axis (rotation by 180\u00b0 around the central C=C bond) and horizontal mirror planes (\u03c3h), which is typical for planar molecules with a double bond.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>cis-CHBr=CHBr (Cis-1,2-Dibromoethene)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2082 axis, \u03c3v mirror plane, no inversion center.<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>C\u2082v<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> In the cis form, the Br atoms are in the same plane, and the molecule possesses a C\u2082 axis (rotation around the C=C bond) and a vertical mirror plane passing through the central bond.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>trans-CHCl=CHCl (Trans-1,2-Dichloroethene)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2082 axis, \u03c3h mirror plane.<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>D\u2082h<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> The trans-configuration of dichloroethene has a C\u2082 axis (rotation by 180\u00b0 around the C=C bond) and horizontal mirror planes (\u03c3h), which makes it a D\u2082h molecule.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">b. Symmetry Elements and Point Groups:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Naphthalene<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2082 axis, \u03c3h, i (inversion center).<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>D\u2082h<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> Naphthalene has multiple symmetry elements, including a C\u2082 axis perpendicular to the molecular plane and an inversion center. It belongs to the D\u2082h point group, characterized by a high degree of symmetry.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Anthracene<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symmetry elements:<\/strong> C\u2082 axis, \u03c3h, i (inversion center).<\/li>\n\n\n\n<li><strong>Point group:<\/strong> <strong>D\u2082h<\/strong><\/li>\n\n\n\n<li><strong>Explanation:<\/strong> Like naphthalene, anthracene has similar symmetry elements, including a C\u2082 axis and an inversion center. It is a larger aromatic molecule but retains the D\u2082h symmetry.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Three Dichlorobenzenes (1,2-Dichlorobenzene, 1,3-Dichlorobenzene, and 1,4-Dichlorobenzene)<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>1,2-Dichlorobenzene<\/strong>: Point group <strong>C\u2082v<\/strong><\/li>\n\n\n\n<li><strong>1,3-Dichlorobenzene<\/strong>: Point group <strong>C\u2082v<\/strong><\/li>\n\n\n\n<li><strong>1,4-Dichlorobenzene<\/strong>: Point group <strong>D\u2082h<\/strong><\/li>\n\n\n\n<li><strong>Symmetry elements:<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>1,2-Dichlorobenzene and 1,3-Dichlorobenzene:<\/strong> C\u2082 axis, \u03c3v mirror planes (vertical through Cl atoms).<\/li>\n\n\n\n<li><strong>1,4-Dichlorobenzene:<\/strong> C\u2082 axis, \u03c3v mirror planes, inversion center.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Explanation:<\/strong> The point group classifications for dichlorobenzenes depend on the relative positions of the chlorine atoms. The 1,2- and 1,3- configurations (both C\u2082v) have mirror planes through the C-Cl bonds and a C\u2082 axis, while 1,4-dichlorobenzene (D\u2082h) has additional symmetry due to its linear, symmetrical arrangement of Cl atoms.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>a. List the symmetry elements of the following molecules and name the point groups to which they belong: (a) NO2, (b) N2O, (c) CHCl3, (d) CH2=CH2, (e) cis-CHBr=CHBr, (f) trans-CHCl=CHCl. b. List the symmetry elements of the following molecules and name the point groups to which they belong: (a) naphthalene, (b) anthracene, (c) the three [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-188097","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/188097","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=188097"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/188097\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=188097"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=188097"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=188097"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}