{"id":3057,"date":"2016-08-24T23:15:29","date_gmt":"2016-08-24T23:15:29","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/?post_type=chapter&#038;p=3057"},"modified":"2016-08-24T23:15:29","modified_gmt":"2016-08-24T23:15:29","slug":"energy-and-covalent-bond-formation","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/chapter\/energy-and-covalent-bond-formation\/","title":{"raw":"Energy and Covalent Bond Formation","rendered":"Energy and Covalent Bond Formation"},"content":{"raw":"<div class=\"x-ck12-data-objectives\">\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li>Define diatomic molecule.<\/li>\r\n \t<li>Draw the potential energy diagram for two atoms that are bonding.<\/li>\r\n \t<li>Define covalent molecule.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox examples\">\r\n<h3><strong>Why do BeCl<sub>2 <\/sub> and LiCl bond differently? <\/strong><\/h3>\r\n<p id=\"x-ck12-YmI4NGViOTIxNDJkZDE4MDY1OWVmYTQxNjY3YzcxOGM.-pqu\">We have learned that halide salts of elements in group1 are typically ionic compounds.\u00a0 We would expect LiCl to exist as Li<sup>+ <\/sup> cations and Cl<sup>\u2013<\/sup>\u00a0anions (and it does).\u00a0 However, if we move one column to the right, lithium\u2019s neighbor beryllium forms a different type of bond altogether.\u00a0 This bond consists of shared electrons between the Be and Cl atoms, not electrostatic attraction among ions.<\/p>\r\n\r\n<\/div>\r\n<p id=\"x-ck12-M2Q2MzMxYTFjMjExYTNiMTNmYTVjNjcxM2MzNmE2YjA.-mbm\">Molecular compounds are those that take the form of an individual molecule.\u00a0 Molecular compounds are generally comprised of two or more nonmetal atoms.\u00a0 Familiar examples include water (H <sub> 2 <\/sub> O), carbon dioxide (CO <sub> 2 <\/sub> ) and ammonia (NH <sub> 3 <\/sub> ).\u00a0 Recall that the molecular formula shows the number of each atom that occurs in a molecule of that compound.\u00a0 One molecule of water contains two hydrogen atoms and one oxygen atom.\u00a0 Hydrogen (H <sub> 2 <\/sub> ) is an example of an element that exists naturally as a diatomic molecule.\u00a0 A <strong> diatomic molecule <\/strong> is a molecule containing two atoms.<\/p>\r\n<p id=\"x-ck12-ZTM1ODc5ZDgwZDk1MDVlY2Y2MTc1YmYxYWJjMzZjMGM.-pda\">Most atoms attain a lower potential energy when they are bonded to other atoms than when they are separated.\u00a0 Consider two isolated hydrogen atoms that are separated by a distance large enough to prevent any interaction between them.\u00a0 At this distance, the potential energy of the system is said to be equal to zero (see <strong> Figure 1<\/strong>).<\/p>\r\n\r\n<div id=\"x-ck12-NDIxMmEwZDM2NjlkMDIxY2UyYmU5ZTMyNWQ2ODQ1YmE.-xwd\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"500\"]<img id=\"x-ck12-OTgwNDUtMTM2MTQ0MDc0OC05Ny05MC1JbWFnZS0tLTI.\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19211428\/20140811155249827945.png\" alt=\"Potential energy of two hydrogen atoms based on distance\" width=\"500\" height=\"333\" longdesc=\"The%20graph%20shows%20how%20the%20potential%20energy%20of%20two%20hydrogen%20atoms%20changes%20as%20a%20function%20of%20their%20separation%20distance.\" \/> Figure 1.\u00a0The graph shows how the potential energy of two hydrogen atoms changes as a function of their separation distance.[\/caption]\r\n\r\n<\/div>\r\n<p id=\"x-ck12-MGE4MjI2YWNkMDU5NmJiOWMwZTRkOGM4MWU3NWM3OTk.-mgi\">As the atoms approach one another, their electron clouds gradually begin to overlap.\u00a0 Now there are several interactions which begin to occur.\u00a0 One is that the single electrons that each hydrogen atom possesses begin to repel each other.\u00a0 This repulsive force would tend to make the potential energy of the system increase.\u00a0 However, the electron of each atom begins to be attracted to the nucleus of the other atom.\u00a0 This attractive force tends to make the potential energy of the system decrease.<\/p>\r\n<p id=\"x-ck12-ZDdiYmEyMWZiZjYxNzI4NzYzMDQyMDU0MGUxMmI3MGY.-2ng\">As the atoms first begin to interact, the attractive force is stronger than the repulsive force and so the potential energy of the system decreases, as seen in the diagram.\u00a0 Remember that the lower potential energy increases the stability of the system.\u00a0 As the two hydrogen atoms move closer and closer together, the potential energy continues to decrease.\u00a0 Eventually, a position is reached where the potential energy is at its lowest possible point.\u00a0 If the hydrogen atoms move any closer together, a third interaction begins to dominate and that is the repulsive force between the two positively-charged nuclei.\u00a0 This repulsive force is very strong as can be seen by the sharp rise in energy at the far left of the diagram.<\/p>\r\n<p id=\"x-ck12-MzEyM2IzMzgyNTY1MDBkNGFmYTc0YmY4MjE0YjEwMTg.-epj\">The point at which the potential energy reached its minimum represents the ideal distance between hydrogen atoms for a stable chemical bond to occur.\u00a0 This type of chemical bond is called a covalent bond.\u00a0 A <strong> covalent bond <\/strong> is a bond in which two atoms share one or more pairs of electrons. \u00a0The single electrons from each of the two hydrogen atoms are shared when the atoms come together to form a hydrogen molecule (H <sub> 2 <\/sub> ).<\/p>\r\n\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Summary<\/h3>\r\n<ul id=\"x-ck12-YzhiZTNlNmRjM2Q3NWRkMjc3MmEyMDAzYzc1YzgyZmM.-qhq\">\r\n \t<li>Covalent bonds are formed when atoms share electrons between them.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Practice<\/h3>\r\n<p id=\"x-ck12-Y2JlMjQ5M2YzMTNmNmRjMzNmZTI0MTMzYzcwM2IzZmY.-iza\">Use the link below to answer the following questions. Please only read the first two pages.<\/p>\r\n<p id=\"x-ck12-NzM0MTk1MmQ0ZGMyMDRkM2I5YzExODdkYTRmZTFiOTM.-kr9\"><a href=\"http:\/\/www.chem.ox.ac.uk\/vrchemistry\/electronsandbonds\/intro1.htm\"> http:\/\/www.chem.ox.ac.uk\/vrchemistry\/electronsandbonds\/intro1.htm <\/a><\/p>\r\n\r\n<ol id=\"x-ck12-ZjM4YWU4M2Y0NTM0ZjQ5ODdjMWY2MTM3NjM2ZDhlMjU.-dri\">\r\n \t<li>Why can two atoms come closer together if they form a covalent bond?<\/li>\r\n \t<li>What role do the electrons have in attracting the two atoms?<\/li>\r\n \t<li>Are two atoms closer together more or less stable than when they are apart?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Review<\/h3>\r\n<ol id=\"x-ck12-MjUwNjdkOWJjNWU2NThhODFhMTc5N2RkNTgzNWFiZWU.-o8q\">\r\n \t<li>What is a diatomic molecule?<\/li>\r\n \t<li>What does lower potential energy do to a system?<\/li>\r\n \t<li>What is the ideal distance for two atoms?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<h2>Glossary<\/h2>\r\n<div class=\"x-ck12-data-vocabulary\">\r\n<ul id=\"x-ck12-YTIyYTUyZTcyOWQzNTQ4YmYzMzNhODdiM2VlMzA3Yjk.-wgz\">\r\n \t<li><strong> covalent bond: <\/strong> A bond in which two atoms share one or more pairs of electrons.<\/li>\r\n \t<li><strong> diatomic molecule: <\/strong> A molecule containing two atoms.<\/li>\r\n<\/ul>\r\n&nbsp;\r\n\r\n<\/div>","rendered":"<div class=\"x-ck12-data-objectives\">\n<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li>Define diatomic molecule.<\/li>\n<li>Draw the potential energy diagram for two atoms that are bonding.<\/li>\n<li>Define covalent molecule.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"textbox examples\">\n<h3><strong>Why do BeCl<sub>2 <\/sub> and LiCl bond differently? <\/strong><\/h3>\n<p id=\"x-ck12-YmI4NGViOTIxNDJkZDE4MDY1OWVmYTQxNjY3YzcxOGM.-pqu\">We have learned that halide salts of elements in group1 are typically ionic compounds.\u00a0 We would expect LiCl to exist as Li<sup>+ <\/sup> cations and Cl<sup>\u2013<\/sup>\u00a0anions (and it does).\u00a0 However, if we move one column to the right, lithium\u2019s neighbor beryllium forms a different type of bond altogether.\u00a0 This bond consists of shared electrons between the Be and Cl atoms, not electrostatic attraction among ions.<\/p>\n<\/div>\n<p id=\"x-ck12-M2Q2MzMxYTFjMjExYTNiMTNmYTVjNjcxM2MzNmE2YjA.-mbm\">Molecular compounds are those that take the form of an individual molecule.\u00a0 Molecular compounds are generally comprised of two or more nonmetal atoms.\u00a0 Familiar examples include water (H <sub> 2 <\/sub> O), carbon dioxide (CO <sub> 2 <\/sub> ) and ammonia (NH <sub> 3 <\/sub> ).\u00a0 Recall that the molecular formula shows the number of each atom that occurs in a molecule of that compound.\u00a0 One molecule of water contains two hydrogen atoms and one oxygen atom.\u00a0 Hydrogen (H <sub> 2 <\/sub> ) is an example of an element that exists naturally as a diatomic molecule.\u00a0 A <strong> diatomic molecule <\/strong> is a molecule containing two atoms.<\/p>\n<p id=\"x-ck12-ZTM1ODc5ZDgwZDk1MDVlY2Y2MTc1YmYxYWJjMzZjMGM.-pda\">Most atoms attain a lower potential energy when they are bonded to other atoms than when they are separated.\u00a0 Consider two isolated hydrogen atoms that are separated by a distance large enough to prevent any interaction between them.\u00a0 At this distance, the potential energy of the system is said to be equal to zero (see <strong> Figure 1<\/strong>).<\/p>\n<div id=\"x-ck12-NDIxMmEwZDM2NjlkMDIxY2UyYmU5ZTMyNWQ2ODQ1YmE.-xwd\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\n<div style=\"width: 510px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" id=\"x-ck12-OTgwNDUtMTM2MTQ0MDc0OC05Ny05MC1JbWFnZS0tLTI.\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19211428\/20140811155249827945.png\" alt=\"Potential energy of two hydrogen atoms based on distance\" width=\"500\" height=\"333\" longdesc=\"The%20graph%20shows%20how%20the%20potential%20energy%20of%20two%20hydrogen%20atoms%20changes%20as%20a%20function%20of%20their%20separation%20distance.\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 1.\u00a0The graph shows how the potential energy of two hydrogen atoms changes as a function of their separation distance.<\/p>\n<\/div>\n<\/div>\n<p id=\"x-ck12-MGE4MjI2YWNkMDU5NmJiOWMwZTRkOGM4MWU3NWM3OTk.-mgi\">As the atoms approach one another, their electron clouds gradually begin to overlap.\u00a0 Now there are several interactions which begin to occur.\u00a0 One is that the single electrons that each hydrogen atom possesses begin to repel each other.\u00a0 This repulsive force would tend to make the potential energy of the system increase.\u00a0 However, the electron of each atom begins to be attracted to the nucleus of the other atom.\u00a0 This attractive force tends to make the potential energy of the system decrease.<\/p>\n<p id=\"x-ck12-ZDdiYmEyMWZiZjYxNzI4NzYzMDQyMDU0MGUxMmI3MGY.-2ng\">As the atoms first begin to interact, the attractive force is stronger than the repulsive force and so the potential energy of the system decreases, as seen in the diagram.\u00a0 Remember that the lower potential energy increases the stability of the system.\u00a0 As the two hydrogen atoms move closer and closer together, the potential energy continues to decrease.\u00a0 Eventually, a position is reached where the potential energy is at its lowest possible point.\u00a0 If the hydrogen atoms move any closer together, a third interaction begins to dominate and that is the repulsive force between the two positively-charged nuclei.\u00a0 This repulsive force is very strong as can be seen by the sharp rise in energy at the far left of the diagram.<\/p>\n<p id=\"x-ck12-MzEyM2IzMzgyNTY1MDBkNGFmYTc0YmY4MjE0YjEwMTg.-epj\">The point at which the potential energy reached its minimum represents the ideal distance between hydrogen atoms for a stable chemical bond to occur.\u00a0 This type of chemical bond is called a covalent bond.\u00a0 A <strong> covalent bond <\/strong> is a bond in which two atoms share one or more pairs of electrons. \u00a0The single electrons from each of the two hydrogen atoms are shared when the atoms come together to form a hydrogen molecule (H <sub> 2 <\/sub> ).<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Summary<\/h3>\n<ul id=\"x-ck12-YzhiZTNlNmRjM2Q3NWRkMjc3MmEyMDAzYzc1YzgyZmM.-qhq\">\n<li>Covalent bonds are formed when atoms share electrons between them.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice<\/h3>\n<p id=\"x-ck12-Y2JlMjQ5M2YzMTNmNmRjMzNmZTI0MTMzYzcwM2IzZmY.-iza\">Use the link below to answer the following questions. Please only read the first two pages.<\/p>\n<p id=\"x-ck12-NzM0MTk1MmQ0ZGMyMDRkM2I5YzExODdkYTRmZTFiOTM.-kr9\"><a href=\"http:\/\/www.chem.ox.ac.uk\/vrchemistry\/electronsandbonds\/intro1.htm\"> http:\/\/www.chem.ox.ac.uk\/vrchemistry\/electronsandbonds\/intro1.htm <\/a><\/p>\n<ol id=\"x-ck12-ZjM4YWU4M2Y0NTM0ZjQ5ODdjMWY2MTM3NjM2ZDhlMjU.-dri\">\n<li>Why can two atoms come closer together if they form a covalent bond?<\/li>\n<li>What role do the electrons have in attracting the two atoms?<\/li>\n<li>Are two atoms closer together more or less stable than when they are apart?<\/li>\n<\/ol>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Review<\/h3>\n<ol id=\"x-ck12-MjUwNjdkOWJjNWU2NThhODFhMTc5N2RkNTgzNWFiZWU.-o8q\">\n<li>What is a diatomic molecule?<\/li>\n<li>What does lower potential energy do to a system?<\/li>\n<li>What is the ideal distance for two atoms?<\/li>\n<\/ol>\n<\/div>\n<h2>Glossary<\/h2>\n<div class=\"x-ck12-data-vocabulary\">\n<ul id=\"x-ck12-YTIyYTUyZTcyOWQzNTQ4YmYzMzNhODdiM2VlMzA3Yjk.-wgz\">\n<li><strong> covalent bond: <\/strong> A bond in which two atoms share one or more pairs of electrons.<\/li>\n<li><strong> diatomic molecule: <\/strong> A molecule containing two atoms.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-3057\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Chemistry Concepts Intermediate. <strong>Authored by<\/strong>: Calbreath, Baxter, et al.. <strong>Provided by<\/strong>: CK12.org. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\">http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":1,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Chemistry Concepts Intermediate\",\"author\":\"Calbreath, Baxter, et al.\",\"organization\":\"CK12.org\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-3057","chapter","type-chapter","status-publish","hentry"],"part":2330,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3057","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":3,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3057\/revisions"}],"predecessor-version":[{"id":3109,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3057\/revisions\/3109"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/parts\/2330"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3057\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/media?parent=3057"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapter-type?post=3057"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/contributor?post=3057"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/license?post=3057"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}