The atomic mass of cobalt-60 (\u2076\u2070Co) is listed as 60.00 g\/mol because it refers to a specific isotope of cobalt that has exactly 27 protons and 33 neutrons. In contrast, the molar mass of cobalt found on the Periodic Table is 58.93 g\/mol, which is the weighted average of all naturally occurring isotopes of cobalt, primarily cobalt-59. The discrepancy arises because the value on the Periodic Table takes into account the natural abundances of all isotopes, while the value for cobalt-60 refers to a single isotope with a known and fixed mass.<\/p>\n\n\n\n
Cobalt-60 is a radioactive isotope that is not found in significant amounts in nature but is produced artificially in nuclear reactors. Since it is a specific isotope, its atomic mass is based on its exact number of protons and neutrons. Protons and neutrons each have an approximate mass of 1 atomic mass unit, so adding 27 protons and 33 neutrons gives a nominal mass number of 60. This is why the atomic mass of \u2076\u2070Co is rounded to 60.00 g\/mol. It is important to note that this is not a measured average but a defined mass based on the isotope’s composition.<\/p>\n\n\n\n
The reason it is a whole number is because it represents the mass number, not a weighted average. The Periodic Table provides average atomic masses based on all stable and naturally occurring isotopes of an element and their relative abundances. In the case of cobalt, cobalt-59 is the only stable isotope found naturally, so the average atomic mass of cobalt is very close to 59 but slightly lower due to precise measurement standards. Cobalt-60, being artificially made and used in medical and industrial applications, is labeled with its mass number for clarity and specificity, leading to its atomic mass being shown as a whole number.<\/p>\n\n\n\n Why is the atomic mass of 60Co 60.00 g\/mol when the molar mass of Co on the Periodic Table is 58.93 g\/mol? What causes it to be different AND a whole number? Paragraph ~ ” The Correct Answer and Explanation is: The atomic mass of cobalt-60 (\u2076\u2070Co) is listed as 60.00 g\/mol because it refers […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-34850","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/34850","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=34850"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/34850\/revisions"}],"predecessor-version":[{"id":34863,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/34850\/revisions\/34863"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=34850"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=34850"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=34850"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner10-299.jpeg\")
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