{"id":84555,"date":"2025-06-01T02:37:19","date_gmt":"2025-06-01T02:37:19","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84555"},"modified":"2025-06-01T02:37:19","modified_gmt":"2025-06-01T02:37:19","slug":"which-one-of-the-following-statements-is-not-correct-7","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-7\/","title":{"rendered":"Which one of the following statements is not correct?"},"content":{"rendered":"

Which one of the following statements is not correct?<\/p>\n

[amp_mcq option1=”Atoms of different elements may have same mass numbers” option2=”Atoms of an element may have different mass numbers” option3=”All the atoms of an element have same number of protons” option4=”All the atoms of an element will always have same number of neutrons” correct=”option4″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2016<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe statement that is not correct is “All the atoms of an element will always have same number of neutrons”.
\n<\/section>\n
\nAtoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. Therefore, not all atoms of an element have the same number of neutrons.
\n<\/section>\n
\nAtoms of different elements can have the same mass number (isobars) if their sum of protons and neutrons is equal (e.g., \u2074\u2070Ar and \u2074\u2070Ca). Atoms of the same element always have the same number of protons. Atoms of the same element can have different mass numbers due to varying numbers of neutrons (isotopes).
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following statements is not correct? [amp_mcq option1=”Atoms of different elements may have same mass numbers” option2=”Atoms of an element may have different mass numbers” option3=”All the atoms of an element have same number of protons” option4=”All the atoms of an element will always have same number of neutrons” correct=”option4″] This question … <\/p>\n

Detailed SolutionWhich one of the following statements is not correct?<\/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":[1098,1162,1096],"class_list":["post-84555","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1098","tag-atomic-structure","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nWhich one of the following statements is not correct?<\/title>\n<meta name=\"description\" content=\"The statement that is not correct is "All the atoms of an element will always have same number of neutrons". Atoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. Therefore, not all atoms of an element have the same number of neutrons.\" \/>\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\/which-one-of-the-following-statements-is-not-correct-7\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following statements is not correct?\" \/>\n<meta property=\"og:description\" content=\"The statement that is not correct is "All the atoms of an element will always have same number of neutrons". Atoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. Therefore, not all atoms of an element have the same number of neutrons.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-7\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T02:37:19+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":"Which one of the following statements is not correct?","description":"The statement that is not correct is \"All the atoms of an element will always have same number of neutrons\". Atoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. Therefore, not all atoms of an element have the same number of neutrons.","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\/which-one-of-the-following-statements-is-not-correct-7\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following statements is not correct?","og_description":"The statement that is not correct is \"All the atoms of an element will always have same number of neutrons\". Atoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. Therefore, not all atoms of an element have the same number of neutrons.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-7\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T02:37:19+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\/which-one-of-the-following-statements-is-not-correct-7\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-7\/","name":"Which one of the following statements is not correct?","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T02:37:19+00:00","dateModified":"2025-06-01T02:37:19+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The statement that is not correct is \"All the atoms of an element will always have same number of neutrons\". Atoms of the same element are defined by having the same number of protons (atomic number). However, atoms of the same element can have different numbers of neutrons, which results in different mass numbers. These variants are called isotopes. 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