{"id":84974,"date":"2025-06-01T02:58:39","date_gmt":"2025-06-01T02:58:39","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84974"},"modified":"2025-06-01T02:58:39","modified_gmt":"2025-06-01T02:58:39","slug":"the-elements-of-which-of-the-following-pairs-are-isobars","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/","title":{"rendered":"The elements of which of the following pairs are isobars?"},"content":{"rendered":"

The elements of which of the following pairs are isobars?<\/p>\n

[amp_mcq option1=”\u00b9\u2081H and \u00b3\u2081H” option2=”\u00b9\u2081H and \u00b2\u2081H” option3=”\u00b9\u00b2\u2086C and \u00b9\u2074\u2086C” option4=”\u2074\u2070\u2081\u2088Ar and \u2074\u2070\u2082\u2080Ca” correct=”option4″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2020<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nIsobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons).
\n<\/section>\n
\nIn option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. Since they have different atomic numbers but the same mass number, they are isobars.
\n<\/section>\n
\nOptions A, B, and C show pairs of isotopes, which are atoms of the same element (same atomic number) but different mass numbers.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

The elements of which of the following pairs are isobars? [amp_mcq option1=”\u00b9\u2081H and \u00b3\u2081H” option2=”\u00b9\u2081H and \u00b2\u2081H” option3=”\u00b9\u00b2\u2086C and \u00b9\u2074\u2086C” option4=”\u2074\u2070\u2081\u2088Ar and \u2074\u2070\u2082\u2080Ca” correct=”option4″] This question was previously asked in UPSC CDS-1 – 2020 Download PDFAttempt Online Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) … <\/p>\n

Detailed SolutionThe elements of which of the following pairs are isobars?<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1087],"tags":[1288,1162,1096],"class_list":["post-84974","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1288","tag-atomic-structure","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nThe elements of which of the following pairs are isobars?<\/title>\n<meta name=\"description\" content=\"Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons). In option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. Since they have different atomic numbers but the same mass number, they are isobars.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The elements of which of the following pairs are isobars?\" \/>\n<meta property=\"og:description\" content=\"Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons). In option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. Since they have different atomic numbers but the same mass number, they are isobars.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T02:58:39+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"The elements of which of the following pairs are isobars?","description":"Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons). In option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. Since they have different atomic numbers but the same mass number, they are isobars.","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:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/","og_locale":"en_US","og_type":"article","og_title":"The elements of which of the following pairs are isobars?","og_description":"Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons). In option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. Since they have different atomic numbers but the same mass number, they are isobars.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T02:58:39+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/","url":"https:\/\/exam.pscnotes.com\/mcq\/the-elements-of-which-of-the-following-pairs-are-isobars\/","name":"The elements of which of the following pairs are isobars?","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T02:58:39+00:00","dateModified":"2025-06-01T02:58:39+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"Isobars are atoms of different chemical elements that have the same mass number (number of protons + neutrons) but different atomic numbers (number of protons). In option D, \u2074\u2070\u2081\u2088Ar (Argon) has an atomic number (Z) of 18 and a mass number (A) of 40. \u2074\u2070\u2082\u2080Ca (Calcium) has an atomic number (Z) of 20 and a mass number (A) of 40. 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