{"id":86998,"date":"2025-06-01T04:25:10","date_gmt":"2025-06-01T04:25:10","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86998"},"modified":"2025-06-01T04:25:10","modified_gmt":"2025-06-01T04:25:10","slug":"which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/","title":{"rendered":"Which one of the following is the correct order of increase of the ato"},"content":{"rendered":"

Which one of the following is the correct order of increase of the atomic radius of the elements?<\/p>\n

[amp_mcq option1=”C < B < Si < Al\" option2=\"C < B < Al < Si\" option3=\"C < Si < B < Al\" option4=\"Si < Al < C < B\" correct=\"option1\"]\n\n\n\n

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This question was previously asked in<\/div>\n
UPSC Geoscientist – 2023<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum).
\nC and B are in Period 2, Group 14 and 13 respectively.
\nSi and Al are in Period 3, Group 14 and 13 respectively.
\nAtomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C.
\nAtomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B.
\nWithin Period 3, Al is to the left of Si, so Al > Si.
\nComparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B).
\nCombining these trends:
\nWithin Period 2: C < B\nWithin Period 3: Si < Al\nComparing across periods: C and B are smaller than Si and Al.\nApproximate covalent radii (in picometers, pm):\nC: 70 pm\nB: 85 pm\nSi: 110 pm\nAl: 125 pm\nOrdering them in increasing radius: C (70) < B (85) < Si (110) < Al (125).\nThe correct order is C < B < Si < Al.\n<\/section>\n
\nAtomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.
\n<\/section>\n
\nExceptions and nuances exist in atomic radius trends, especially for transition metals and noble gases. The type of radius (covalent, ionic, van der Waals) also matters depending on the bonding situation.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following is the correct order of increase of the atomic radius of the elements? [amp_mcq option1=”C < B < Si < Al\" option2=\"C < B < Al < Si\" option3=\"C < Si < B < Al\" option4=\"Si < Al < C < B\" correct=\"option1\"] This question was previously asked in UPSC ... \n\n

Detailed SolutionWhich one of the following is the correct order of increase of the ato<\/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":[1091],"tags":[1105,1162,1096],"class_list":["post-86998","post","type-post","status-publish","format-standard","hentry","category-upsc-geoscientist","tag-1105","tag-atomic-structure","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nWhich one of the following is the correct order of increase of the ato<\/title>\n<meta name=\"description\" content=\"The elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum). C and B are in Period 2, Group 14 and 13 respectively. Si and Al are in Period 3, Group 14 and 13 respectively. Atomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C. Atomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B. Within Period 3, Al is to the left of Si, so Al > Si. Comparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B). Combining these trends: Within Period 2: C < B Within Period 3: Si < Al Comparing across periods: C and B are smaller than Si and Al. Approximate covalent radii (in picometers, pm): C: 70 pm B: 85 pm Si: 110 pm Al: 125 pm Ordering them in increasing radius: C (70) < B (85) < Si (110) < Al (125). The correct order is C < B < Si < Al. Atomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.\" \/>\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-is-the-correct-order-of-increase-of-the-ato\/\" \/>\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 is the correct order of increase of the ato\" \/>\n<meta property=\"og:description\" content=\"The elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum). C and B are in Period 2, Group 14 and 13 respectively. Si and Al are in Period 3, Group 14 and 13 respectively. Atomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C. Atomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B. Within Period 3, Al is to the left of Si, so Al > Si. Comparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B). Combining these trends: Within Period 2: C < B Within Period 3: Si < Al Comparing across periods: C and B are smaller than Si and Al. Approximate covalent radii (in picometers, pm): C: 70 pm B: 85 pm Si: 110 pm Al: 125 pm Ordering them in increasing radius: C (70) < B (85) < Si (110) < Al (125). The correct order is C < B < Si < Al. Atomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T04:25:10+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 is the correct order of increase of the ato","description":"The elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum). C and B are in Period 2, Group 14 and 13 respectively. Si and Al are in Period 3, Group 14 and 13 respectively. Atomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C. Atomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B. Within Period 3, Al is to the left of Si, so Al > Si. Comparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B). Combining these trends: Within Period 2: C < B Within Period 3: Si < Al Comparing across periods: C and B are smaller than Si and Al. Approximate covalent radii (in picometers, pm): C: 70 pm B: 85 pm Si: 110 pm Al: 125 pm Ordering them in increasing radius: C (70) < B (85) < Si (110) < Al (125). The correct order is C < B < Si < Al. Atomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.","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-is-the-correct-order-of-increase-of-the-ato\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following is the correct order of increase of the ato","og_description":"The elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum). C and B are in Period 2, Group 14 and 13 respectively. Si and Al are in Period 3, Group 14 and 13 respectively. Atomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C. Atomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B. Within Period 3, Al is to the left of Si, so Al > Si. Comparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B). Combining these trends: Within Period 2: C < B Within Period 3: Si < Al Comparing across periods: C and B are smaller than Si and Al. Approximate covalent radii (in picometers, pm): C: 70 pm B: 85 pm Si: 110 pm Al: 125 pm Ordering them in increasing radius: C (70) < B (85) < Si (110) < Al (125). The correct order is C < B < Si < Al. Atomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T04:25:10+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-is-the-correct-order-of-increase-of-the-ato\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/","name":"Which one of the following is the correct order of increase of the ato","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T04:25:10+00:00","dateModified":"2025-06-01T04:25:10+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The elements are C (Carbon), B (Boron), Si (Silicon), and Al (Aluminum). C and B are in Period 2, Group 14 and 13 respectively. Si and Al are in Period 3, Group 14 and 13 respectively. Atomic radius generally decreases across a period from left to right due to increasing nuclear charge pulling the electron cloud closer. So, B > C. Atomic radius generally increases down a group due to the addition of electron shells. So, Si > C and Al > B. Within Period 3, Al is to the left of Si, so Al > Si. Comparing elements across periods and groups: Period 3 elements (Si, Al) are generally larger than Period 2 elements (C, B). Combining these trends: Within Period 2: C < B Within Period 3: Si < Al Comparing across periods: C and B are smaller than Si and Al. Approximate covalent radii (in picometers, pm): C: 70 pm B: 85 pm Si: 110 pm Al: 125 pm Ordering them in increasing radius: C (70) < B (85) < Si (110) < Al (125). The correct order is C < B < Si < Al. Atomic radius decreases across a period and increases down a group. The increase in radius down a group due to adding a new electron shell is usually more significant than the decrease across a period due to increasing nuclear charge.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-the-correct-order-of-increase-of-the-ato\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC Geoscientist","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-geoscientist\/"},{"@type":"ListItem","position":3,"name":"Which one of the following is the correct order of increase of the ato"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/86998","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=86998"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/86998\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=86998"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=86998"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=86998"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}