{"id":24929,"date":"2025-06-18T19:28:02","date_gmt":"2025-06-18T19:28:02","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=24929"},"modified":"2025-06-18T19:28:04","modified_gmt":"2025-06-18T19:28:04","slug":"draw-an-mo-energy-diagram-and-predict-the-bond-order-of-be2-and-be2","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/draw-an-mo-energy-diagram-and-predict-the-bond-order-of-be2-and-be2\/","title":{"rendered":"Draw an MO energy diagram and predict the bond order of Be2+ and Be2-."},"content":{"rendered":"\n<p>Draw an MO energy diagram and predict the bond order of Be2+ and Be2-. Do you expect these molecules to exist in the gas phase?<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-green-cyan-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p><strong>Answer:<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Molecular Orbital (MO) Diagrams:<\/strong><\/h3>\n\n\n\n<p>For beryllium (Be), atomic number = 4.<br>Each neutral Be atom has 4 electrons. So:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Be\u2082<\/strong> has 8 total electrons (4 from each atom).<\/li>\n\n\n\n<li><strong>Be\u2082\u207a<\/strong> has 7 total electrons.<\/li>\n\n\n\n<li><strong>Be\u2082\u207b<\/strong> has 9 total electrons.<\/li>\n<\/ul>\n\n\n\n<p>The MO diagram for Be\u2082, Be\u2082\u207a, and Be\u2082\u207b (for elements up to atomic number 7) follows this order:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">scssCopyEdit<code>\u03c3(1s) &lt; \u03c3*(1s) &lt; \u03c3(2s) &lt; \u03c3*(2s)\n<\/code><\/pre>\n\n\n\n<p>Now we fill in the electrons:<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Be\u2082\u207a (7 electrons)<\/strong><\/h3>\n\n\n\n<p>MO configuration:<br>\u03c3(1s)\u00b2 \u03c3*(1s)\u00b2 \u03c3(2s)\u00b2 \u03c3*(2s)\u00b9<\/p>\n\n\n\n<p>Bond order = (Number of bonding electrons \u2212 Number of antibonding electrons) \u00f7 2<br>= (4 bonding \u2212 3 antibonding) \u00f7 2 = 0.5<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Be\u2082\u207b (9 electrons)<\/strong><\/h3>\n\n\n\n<p>MO configuration:<br>\u03c3(1s)\u00b2 \u03c3*(1s)\u00b2 \u03c3(2s)\u00b2 \u03c3*(2s)\u00b2 \u03c0(2p)\u00b9 \u2192 but the \u03c0(2p) orbital is not filled until boron and higher, so stick to \u03c3(2s)*<\/p>\n\n\n\n<p>Thus, 9th electron goes into \u03c0(2p) for elements with p-orbitals involved (Be does not yet include p-orbitals), so the configuration remains:<\/p>\n\n\n\n<p>\u03c3(1s)\u00b2 \u03c3*(1s)\u00b2 \u03c3(2s)\u00b2 \u03c3*(2s)\u00b3<\/p>\n\n\n\n<p>Bond order = (4 bonding \u2212 5 antibonding) \u00f7 2 = \u22120.5<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Existence in the Gas Phase:<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Be\u2082\u207a<\/strong> has a bond order of 0.5. It has a weak bond and could exist briefly in the gas phase under experimental or high-energy conditions, but it is not stable.<\/li>\n\n\n\n<li><strong>Be\u2082\u207b<\/strong> has a negative bond order, indicating that it is unstable and unlikely to exist under normal conditions.<\/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\"><strong>Conclusion:<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Be\u2082\u207a:<\/strong> Bond order = 0.5 \u2192 marginally stable, may exist briefly in gas phase.<\/li>\n\n\n\n<li><strong>Be\u2082\u207b:<\/strong> Bond order = \u22120.5 \u2192 not expected to exist, unstable.<\/li>\n<\/ul>\n\n\n\n<p>Therefore, <strong>Be\u2082\u207a<\/strong> might be detected in specific high-energy environments, but <strong>Be\u2082\u207b<\/strong> is not likely to exist in the gas phase.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"852\" height=\"1024\" src=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-30.jpeg\" alt=\"\" class=\"wp-image-24934\" srcset=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-30.jpeg 852w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-30-250x300.jpeg 250w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-30-768x923.jpeg 768w\" sizes=\"auto, (max-width: 852px) 100vw, 852px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Draw an MO energy diagram and predict the bond order of Be2+ and Be2-. Do you expect these molecules to exist in the gas phase? The Correct Answer and Explanation is: Answer: Molecular Orbital (MO) Diagrams: For beryllium (Be), atomic number = 4.Each neutral Be atom has 4 electrons. So: The MO diagram for Be\u2082, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-24929","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24929","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=24929"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24929\/revisions"}],"predecessor-version":[{"id":24936,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/24929\/revisions\/24936"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=24929"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=24929"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=24929"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}