{"id":205386,"date":"2025-03-24T11:52:57","date_gmt":"2025-03-24T11:52:57","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=205386"},"modified":"2025-03-24T11:52:59","modified_gmt":"2025-03-24T11:52:59","slug":"an-isotope-of-which-element-is-used-as-the-standard-for-the-relative-mass-scale-for-atoms","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/03\/24\/an-isotope-of-which-element-is-used-as-the-standard-for-the-relative-mass-scale-for-atoms\/","title":{"rendered":"An isotope of which element is used as the standard for the relative mass scale for atoms"},"content":{"rendered":"\n<p>An isotope of which element is used as the standard for the relative mass scale for atoms?<\/p>\n\n\n\n<p>A) carbon<\/p>\n\n\n\n<p>B) oxygen<\/p>\n\n\n\n<p>C) hydrogen<\/p>\n\n\n\n<p>D) helium<\/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<p>The correct answer is <strong>A) carbon<\/strong>.<\/p>\n\n\n\n<p>The standard for the relative mass scale of atoms is based on the isotope <strong>carbon-12<\/strong> (C-12). This choice was made due to the isotope&#8217;s stability and its abundance in nature. The atomic mass unit (amu), also known as the unified atomic mass unit (u), is defined as 1\/12th the mass of a single carbon-12 atom.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<p>The concept of atomic mass is crucial in chemistry and physics, as it provides a way to quantify the mass of atoms and molecules. The relative atomic mass is the ratio of the mass of an atom to 1\/12th the mass of a carbon-12 atom, which has been set as the standard reference.<\/p>\n\n\n\n<p>The <strong>carbon-12 isotope<\/strong> was chosen as the standard for a few key reasons:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Stability<\/strong>: Carbon-12 is a stable isotope, meaning it doesn&#8217;t decay over time, which makes it reliable as a reference.<\/li>\n\n\n\n<li><strong>Abundance<\/strong>: Carbon is a naturally abundant element in the universe, especially in organic compounds, which makes carbon-12 widely available for scientific measurements.<\/li>\n\n\n\n<li><strong>Historical Importance<\/strong>: Before the adoption of carbon-12, hydrogen (specifically the isotope protium, which is just a single proton) was considered as a reference, but it was decided that carbon-12 offered a more practical and precise standard for atomic mass measurements.<\/li>\n<\/ol>\n\n\n\n<p>The choice of carbon-12 also helps avoid the complications associated with isotopes like oxygen or helium, which have different abundances and decay patterns, and hydrogen, which has an atomic mass much smaller than carbon-12, leading to less convenient scaling for most elements.<\/p>\n\n\n\n<p>Thus, when chemists and physicists refer to the atomic mass of elements, they are referring to the mass relative to the carbon-12 standard.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/03\/image-1291.png\" alt=\"\" class=\"wp-image-205387\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>An isotope of which element is used as the standard for the relative mass scale for atoms? A) carbon B) oxygen C) hydrogen D) helium The correct answer and explanation is : The correct answer is A) carbon. The standard for the relative mass scale of atoms is based on the isotope carbon-12 (C-12). This [&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-205386","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/205386","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=205386"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/205386\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=205386"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=205386"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=205386"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}