{"id":90127,"date":"2026-11-03T11:29:10","date_gmt":"2026-11-03T11:29:10","guid":{"rendered":"https:\/\/jlindemann.se\/homepage\/?p=90127"},"modified":"2026-11-03T11:29:27","modified_gmt":"2026-11-03T11:29:27","slug":"how-to-read-an-element-tile","status":"publish","type":"post","link":"https:\/\/jlindemann.se\/homepage\/how-to-read-an-element-tile\/","title":{"rendered":"How to read an element tile"},"content":{"rendered":"\n

Why does carbon’s overview say 12.011 and not just 12?<\/strong> Every square on the periodic table packs the same few facts into a tiny space. Once you know how to read one tile, you can easilty understand all 118.<\/p>\n\n\n\n

The four parts of a tile<\/h2>\n\n\n\n

Tap carbon (C)<\/strong> in Atomic and look at the top of its page. You’ll find the same four pieces of information shown on every tile:<\/p>\n\n\n\n

Part<\/th>Carbon example<\/th>What it tells you<\/th><\/tr>
Atomic number<\/td>6<\/td>The number of protons, which decides the element (Guide 2)<\/td><\/tr>
Symbol<\/td>C<\/td>A one- or two-letter short name used in formulas worldwide<\/td><\/tr>
Name<\/td>Carbon<\/td>The element’s full name<\/td><\/tr>
Atomic mass<\/td>12.011<\/td>How heavy an average atom is, compared with 1\/12 of a carbon-12 atom<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Symbols<\/strong> always start with a capital letter, and any second letter is lowercase: Co is cobalt, but CO is carbon monoxide. Many symbols come from the English name (O for oxygen), but some come from Latin: Fe for iron (ferrum<\/em>), Au for gold (aurum<\/em>), Na for sodium (natrium<\/em>) and K for potassium (kalium<\/em>).<\/p>\n\n\n\n

The atomic number<\/strong> is always a whole number and increases by exactly one from each element to the next. That’s how the table is ordered (Guide 4).<\/p>\n\n\n\n

Why atomic masses have decimals<\/h2>\n\n\n\n

Protons and neutrons each weigh about 1 unit, so you might expect every atomic mass to be a whole number. The decimals appear because most elements are a mixture of isotopes<\/strong>: atoms with the same number of protons but different numbers of neutrons. The mass on the tile is an average<\/em>, weighted by how common each isotope is.<\/p>\n\n\n\n

Chlorine is a clear example. It exists as chlorine-35 and chlorine-37, and its atomic mass is about 35.45<\/strong>. That value sits much closer to 35 than to 37, which tells you that roughly three in every four chlorine atoms are chlorine-35.<\/p>\n\n\n\n

The composition of an element can vary slightly depending on where a sample comes from, so its average mass varies too. For that reason, the IUPAC commission responsible for atomic weights gives some elements a range instead of a single number. Chlorine’s is 35.446\u201335.457 and carbon’s is 12.0096\u201312.0116. Boron’s atomic weight, for example, falls anywhere between 10.806 and 10.821 depending on its source. For everyday calculations, a single rounded value such as 35.45 or 12.011 is what you’ll use.<\/p>\n\n\n\n

\n

Tip:<\/strong> Some heavy elements are shown with a whole number in brackets, such as [294] for oganesson. These have no stable isotopes, so the number is the mass of their longest-lived known isotope.<\/p>\n<\/blockquote>\n\n\n\n

You’ll explore isotopes properly in Guide 17.<\/p>\n\n\n\n

Sources<\/strong>:<\/p>\n\n\n\n

https:\/\/www.ciaaw.org\/pubs\/Periodic_Table_Isotopes_2013_Sep.pdf<\/a><\/p>\n\n\n\n

https:\/\/ciaaw.org\/natural-variations.htm<\/a><\/p>\n\n\n\n

Try it in Atomic<\/h2>\n\n\n\n
    \n
  1. Open iron<\/strong>, gold<\/strong>, sodium<\/strong> and potassium<\/strong>. Which symbols don’t match their English names?<\/li>\n\n\n\n
  2. Compare the atomic masses of fluorine<\/strong> and chlorine<\/strong>. Which one is closer to a whole number?<\/li>\n\n\n\n
  3. Open the isotope table for chlorine<\/strong> and find chlorine-35 and chlorine-37.<\/li>\n\n\n\n
  4. Scroll to the end of the table and check how the atomic mass is shown for oganesson (Og)<\/strong>.<\/li>\n<\/ol>\n\n\n\n

    Ask Atomic<\/h2>\n\n\n\n
      \n
    • “Why is the symbol for lead Pb?”<\/li>\n\n\n\n
    • “Why is the atomic mass of copper not a whole number?”<\/li>\n<\/ul>\n\n\n\n

      Check yourself<\/h2>\n\n\n\n

      1. Which part of a tile tells you the number of protons?<\/strong><\/p>\n\n\n\n

        \n
      • A) The atomic mass<\/li>\n\n\n\n
      • B) The atomic number<\/li>\n\n\n\n
      • C) The symbol<\/li>\n<\/ul>\n\n\n\n

        2. Why is chlorine’s atomic mass about 35.45 rather than a whole number?<\/strong><\/p>\n\n\n\n

          \n
        • A) It’s an average of chlorine’s isotopes<\/li>\n\n\n\n
        • B) Electrons add the extra 0.45<\/li>\n\n\n\n
        • C) It has been rounded incorrectly<\/li>\n<\/ul>\n\n\n\n

          3. Which symbol is written correctly for cobalt?<\/strong><\/p>\n\n\n\n

            \n
          • A) CO<\/li>\n\n\n\n
          • B) co<\/li>\n\n\n\n
          • C) Co<\/li>\n<\/ul>\n\n\n\n
            Show answers<\/summary>\n

            1. B \u00b7 2. A \u00b7 3. C<\/p>\n<\/details>\n","protected":false},"excerpt":{"rendered":"

            Why does carbon’s overview say 12.011 and not just 12? Every square on the periodic table packs the same few facts into a tiny space. Once you know how to read one tile, you can easilty understand all 118. The four parts of a tile Tap carbon (C) in Atomic and look at the top […]<\/p>\n","protected":false},"author":2,"featured_media":2357,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_hide_featured_image":false,"_jetpack_featured_image_duplicate_dismissed":0,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[50,1],"tags":[55,60,58],"class_list":["post-90127","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-guides","category-uncategorized","tag-beginner","tag-guides","tag-introduction"],"jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/paQrWz-nrF","jetpack-related-posts":[{"id":9001,"url":"https:\/\/jlindemann.se\/homepage\/getting-started-with-atomic\/","url_meta":{"origin":90127,"position":0},"title":"Getting Started with Atomic","author":"Jonatan Lindemann","date":"November 2, 2026","format":false,"excerpt":"A four-minute tour of Atomic: the periodic table, element pages, tables and tools, and the Ask Atomic chemistry assistant.","rel":"","context":"In "Guides"","block_context":{"text":"Guides","link":"https:\/\/jlindemann.se\/homepage\/category\/guides\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/jlindemann.se\/homepage\/wp-content\/uploads\/2025\/08\/feature-1.png?fit=804%2C603&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/jlindemann.se\/homepage\/wp-content\/uploads\/2025\/08\/feature-1.png?fit=804%2C603&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/jlindemann.se\/homepage\/wp-content\/uploads\/2025\/08\/feature-1.png?fit=804%2C603&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/jlindemann.se\/homepage\/wp-content\/uploads\/2025\/08\/feature-1.png?fit=804%2C603&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":90118,"url":"https:\/\/jlindemann.se\/homepage\/what-is-an-element\/","url_meta":{"origin":90127,"position":1},"title":"What is an element?","author":"admin","date":"November 2, 2026","format":false,"excerpt":"Everything you breathe or touch have one thing in common. 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