{"id":3255,"date":"2025-05-27T18:34:34","date_gmt":"2025-05-27T13:04:34","guid":{"rendered":"https:\/\/leverageedu.com\/questions-answers\/?p=3255"},"modified":"2025-05-27T18:34:37","modified_gmt":"2025-05-27T13:04:37","slug":"ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse","status":"publish","type":"post","link":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/","title":{"rendered":"Ionisation energy and electron affinity are defined as what?"},"content":{"rendered":"\n

Answer: <\/strong>The correct answer is (C) Enthalpy. Ionisation energy (IE) and electron affinity (EA) are both defined in terms of enthalpy. Enthalpy means the heat energy change that happens during a chemical reaction at constant pressure. When we remove an electron from a gaseous atom, energy is absorbed, and this is called ionisation energy. When an atom in the gaseous state gains an electron, energy is usually released, and that is called electron affinity. In both cases, energy is either taken in or given out, which is measured as enthalpy change.<\/p>\n\n\n\n

Complete Answer:<\/strong><\/p>\n\n\n\n

Ionisation energy (IE) and electron affinity (EA) are both defined in terms of enthalpy (\u0394H). Enthalpy refers to the heat energy change that occurs during a chemical process at constant pressure. When an electron is removed from a gaseous atom, energy is absorbed, and this process is called ionisation energy. For example:<\/p>\n\n\n\n

X(g)\u2192X<\/strong>+<\/sup><\/strong>(g)+e<\/strong>\u2013<\/sup><\/strong>\u00a0 \u0394H=+IE<\/strong><\/p>\n\n\n\n

Here, a neutral atom X(g) loses one electron to form a positive ion X+<\/sup><\/strong>(g), and the energy absorbed is the ionisation energy.<\/p>\n\n\n\n

On the other hand, when a gaseous atom gains an electron, energy is usually released, and this process is called electron affinity. For example:<\/p>\n\n\n\n

X(g)+e<\/strong>\u2013<\/sup><\/strong>\u2192X<\/strong>\u2013<\/sup><\/strong>(g)\u00a0 \u0394H=\u2212EA<\/strong><\/p>\n\n\n\n

In this case, a neutral atom X(g) gains an electron to form a negative ion X\u2013<\/sup>(g), and the energy released is the electron affinity. In both cases, the energy absorbed or released is measured as a change in enthalpy (\u0394H). That\u2019s why ionisation energy and electron affinity are both types of enthalpy changes, making (C) Enthalpy the correct answer.<\/p>\n\n\n\n

Let\u2019s understand why other options are incorrect:<\/p>\n\n\n\n

(A) Equilibrium:<\/strong> Equilibrium is a state where the rate of the forward reaction equals the rate of the backward reaction in a chemical system. It refers to the balance in a reaction, not to the energy involved. Ionisation energy and electron affinity deal with the energy change when electrons are removed or added, not with the balance of chemical reactions. So, equilibrium does not define them and is not the correct answer.<\/p>\n\n\n\n

(B) Spontaneity:<\/strong> Spontaneity refers to whether a reaction happens on its own without needing external energy. It depends on Gibbs free energy (\u0394G), which considers both enthalpy (\u0394H) and entropy (\u0394S). While IE and EA involve enthalpy, they do not directly determine whether the reaction is spontaneous. A reaction can have high ionisation energy or low electron affinity and still be spontaneous or non-spontaneous depending on other factors. So, spontaneity is not the defining concept here.<\/p>\n\n\n\n

(D) None:<\/strong> This option means that none of the choices are correct, but that is not true. As clearly explained, both ionisation energy and electron affinity involve enthalpy changes because they measure how much heat energy is absorbed or released when an electron is removed or added to a gaseous atom. Hence, (C) is definitely correct, and selecting \u201cNone\u201d would be incorrect.<\/p>\n\n\n\n

So, the correct and most suitable answer is (C) Enthalpy, because both ionisation energy (IE) and electron affinity (EA) are energy changes that are measured in terms of enthalpy (\u0394H). These processes involve adding or removing electrons, with heat energy either absorbed or released, making enthalpy the key concept that defines them.<\/p>\n\n\n\n

Common Chemistry Doubts:<\/strong><\/p>\n\n\n\n

What happens when calcium reacts with water?<\/strong><\/a><\/td>How many Structural Isomers are Possible for Pentane?<\/strong><\/a><\/td><\/tr>
What is the Chemical Name of Bleaching Powder?<\/strong><\/a><\/td>What is called \u2018black gold\u2019?<\/strong><\/a><\/td><\/tr>
Is Calcium Hydroxide a weak alkali?<\/strong><\/a><\/td>The correct sequence of increasing covalent character is represented by<\/strong><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"Answer: The correct answer is (C) Enthalpy. Ionisation energy (IE) and electron affinity (EA) are both defined in…\n","protected":false},"author":115,"featured_media":3256,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"editor_notices":[],"footnotes":""},"categories":[10,4],"tags":[],"class_list":{"0":"post-3255","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-chemistry","8":"category-science"},"yoast_head":"\nIonisation energy and electron affinity are defined as what?<\/title>\n<meta name=\"description\" content=\"Ionisation energy and electron affinity are both defined as enthalpy changes because they involve energy absorbed or released when electrons are removed or added to atoms.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Ionisation energy and electron affinity are defined as what?\" \/>\n<meta property=\"og:description\" content=\"Ionisation energy and electron affinity are both defined as enthalpy changes because they involve energy absorbed or released when electrons are removed or added to atoms.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/\" \/>\n<meta property=\"og:site_name\" content=\"Questions & Answers\" \/>\n<meta property=\"article:published_time\" content=\"2025-05-27T13:04:34+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-05-27T13:04:37+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"1024\" \/>\n\t<meta property=\"og:image:height\" content=\"640\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"author\" content=\"Mohit Rajak\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Mohit Rajak\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Ionisation energy and electron affinity are defined as what?","description":"Ionisation energy and electron affinity are both defined as enthalpy changes because they involve energy absorbed or released when electrons are removed or added to atoms.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/","og_locale":"en_US","og_type":"article","og_title":"Ionisation energy and electron affinity are defined as what?","og_description":"Ionisation energy and electron affinity are both defined as enthalpy changes because they involve energy absorbed or released when electrons are removed or added to atoms.","og_url":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/","og_site_name":"Questions & Answers","article_published_time":"2025-05-27T13:04:34+00:00","article_modified_time":"2025-05-27T13:04:37+00:00","og_image":[{"width":1024,"height":640,"url":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp","type":"image\/webp"}],"author":"Mohit Rajak","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Mohit Rajak","Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#article","isPartOf":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/"},"author":{"name":"Mohit Rajak","@id":"https:\/\/leverageedu.com\/questions-answers\/#\/schema\/person\/397ac1e3cf645bddda6f314b3308005b"},"headline":"Ionisation energy and electron affinity are defined as what?","datePublished":"2025-05-27T13:04:34+00:00","dateModified":"2025-05-27T13:04:37+00:00","mainEntityOfPage":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/"},"wordCount":600,"commentCount":0,"image":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#primaryimage"},"thumbnailUrl":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp","articleSection":["Chemistry","Science"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/","url":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/","name":"Ionisation energy and electron affinity are defined as what?","isPartOf":{"@id":"https:\/\/leverageedu.com\/questions-answers\/#website"},"primaryImageOfPage":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#primaryimage"},"image":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#primaryimage"},"thumbnailUrl":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp","datePublished":"2025-05-27T13:04:34+00:00","dateModified":"2025-05-27T13:04:37+00:00","author":{"@id":"https:\/\/leverageedu.com\/questions-answers\/#\/schema\/person\/397ac1e3cf645bddda6f314b3308005b"},"description":"Ionisation energy and electron affinity are both defined as enthalpy changes because they involve energy absorbed or released when electrons are removed or added to atoms.","breadcrumb":{"@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#primaryimage","url":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp","contentUrl":"https:\/\/blogassets.leverageedu.com\/media\/uploads\/sites\/5\/2025\/05\/27182510\/Ionisation-energy-and-electron-affinity-are-defined-as-what.webp","width":1024,"height":640,"caption":"Ionisation energy and electron affinity are defined as what"},{"@type":"BreadcrumbList","@id":"https:\/\/leverageedu.com\/questions-answers\/ionisation-energy-and-electron-affinity-are-defined-as-what-class-11-chemistry-cbse\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/leverageedu.com\/questions-answers\/"},{"@type":"ListItem","position":2,"name":"Ionisation energy and electron affinity are defined as what?"}]},{"@type":"WebSite","@id":"https:\/\/leverageedu.com\/questions-answers\/#website","url":"https:\/\/leverageedu.com\/questions-answers\/","name":"Questions & Answers","description":"We Help Build Awesome Careers","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/leverageedu.com\/questions-answers\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/leverageedu.com\/questions-answers\/#\/schema\/person\/397ac1e3cf645bddda6f314b3308005b","name":"Mohit Rajak","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/093f38769270ccfe9d0812e2f23b6fe26cf8c7ceb4e4ace3482fdd4b80b122e9?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/093f38769270ccfe9d0812e2f23b6fe26cf8c7ceb4e4ace3482fdd4b80b122e9?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/093f38769270ccfe9d0812e2f23b6fe26cf8c7ceb4e4ace3482fdd4b80b122e9?s=96&d=mm&r=g","caption":"Mohit Rajak"},"description":"I\u2019m Mohit Rajak, a soul deeply entwined with the rhythm of words. I find peace and purpose in crafting verses that dance between the lines of poetry. With my pen as my wand, I weave intricate tales and heartfelt musings, breathing life into the blank canvas of each page. Blogging is my window to the world way of sharing thoughts, emotions, and a perspective uniquely my own. Every word I write is a brushstroke in the ever-evolving painting of my literary journey.","sameAs":["https:\/\/www.instagram.com\/xx_a.m.strings_xiv\/","https:\/\/www.linkedin.com\/in\/mohit-rajak-a9a5a2162\/"],"url":"https:\/\/leverageedu.com\/questions-answers\/author\/mohit\/"}]}},"acf":[],"_links":{"self":[{"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/posts\/3255","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/users\/115"}],"replies":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/comments?post=3255"}],"version-history":[{"count":4,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/posts\/3255\/revisions"}],"predecessor-version":[{"id":3261,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/posts\/3255\/revisions\/3261"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/media\/3256"}],"wp:attachment":[{"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/media?parent=3255"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/categories?post=3255"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/leverageedu.com\/questions-answers\/wp-json\/wp\/v2\/tags?post=3255"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}