{"id":238608,"date":"2025-06-18T08:57:22","date_gmt":"2025-06-18T08:57:22","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=238608"},"modified":"2025-06-18T08:57:24","modified_gmt":"2025-06-18T08:57:24","slug":"periodic-properties-of-the-elements-your-turn-7","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/18\/periodic-properties-of-the-elements-your-turn-7\/","title":{"rendered":"Periodic Properties of the Elements Your Turn 7"},"content":{"rendered":"\n

Periodic Properties of the Elements Your Turn 7.1 Estimate the approximate effective nuclear charge of scandium. Would you expect scandium’s valence electrons to be held more or less tightly than those of potassium? Use electron configurations to justify your answer.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

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

The approximate effective nuclear charge (Z_eff<\/strong>) of scandium (Sc) is about +3<\/strong>.<\/p>\n\n\n\n

Scandium\u2019s valence electrons are held more tightly<\/strong> than those of potassium.<\/p>\n\n\n\n

\n\n\n\n

Explanation (Approx. 300 words):<\/strong><\/p>\n\n\n\n

To estimate the effective nuclear charge (Z_eff), we use the formula:<\/p>\n\n\n\n

Z_eff = Z \u2212 S<\/strong><\/p>\n\n\n\n

Where:<\/p>\n\n\n\n

    \n
  • Z<\/strong> is the atomic number<\/li>\n\n\n\n
  • S<\/strong> is the shielding or screening constant (approximate number of core electrons)<\/li>\n<\/ul>\n\n\n\n

    Scandium (Sc) has an atomic number of 21<\/strong>. Its electron configuration is:<\/p>\n\n\n\n

    1s\u00b2 2s\u00b2 2p\u2076 3s\u00b2 3p\u2076 4s\u00b2 3d\u00b9<\/strong><\/p>\n\n\n\n

    The electrons in the n = 1, 2, and 3<\/strong> shells (that is, 1s through 3p) are considered core electrons. These add up to:<\/p>\n\n\n\n

    2 (1s\u00b2) + 2 (2s\u00b2) + 6 (2p\u2076) + 2 (3s\u00b2) + 6 (3p\u2076) = 18 core electrons<\/strong><\/p>\n\n\n\n

    So, Z = 21 and S \u2248 18, giving:<\/p>\n\n\n\n

    Z_eff \u2248 21 \u2212 18 = +3<\/strong><\/p>\n\n\n\n

    This effective nuclear charge is experienced by scandium\u2019s outermost electrons, primarily the 4s\u00b2 and 3d\u00b9<\/strong> electrons. Since Z_eff is relatively high, these valence electrons are attracted more strongly by the nucleus.<\/p>\n\n\n\n

    Now, compare this with potassium (K)<\/strong>, atomic number 19. Its configuration is:<\/p>\n\n\n\n

    1s\u00b2 2s\u00b2 2p\u2076 3s\u00b2 3p\u2076 4s\u00b9<\/strong><\/p>\n\n\n\n

    Potassium has 18 core electrons as well (same as scandium), so:<\/p>\n\n\n\n

    Z_eff \u2248 19 \u2212 18 = +1<\/strong><\/p>\n\n\n\n

    This means potassium\u2019s single 4s electron experiences a much weaker nuclear pull than scandium\u2019s valence electrons. As a result, scandium\u2019s valence electrons are held more tightly<\/strong> than those of potassium.<\/p>\n\n\n\n

    This is consistent with periodic trends. Across a period, effective nuclear charge increases, and electrons are held more tightly. Therefore, scandium (to the right of potassium in Period 4) holds its valence electrons more strongly.<\/p>\n\n\n\n

    \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

    Periodic Properties of the Elements Your Turn 7.1 Estimate the approximate effective nuclear charge of scandium. Would you expect scandium’s valence electrons to be held more or less tightly than those of potassium? Use electron configurations to justify your answer. The Correct Answer and Explanation is: Correct Answer: The approximate effective nuclear charge (Z_eff) of […]<\/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-238608","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/238608","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=238608"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/238608\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=238608"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=238608"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=238608"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}