{"id":3643,"date":"2023-01-09T10:09:25","date_gmt":"2023-01-09T10:09:25","guid":{"rendered":"https:\/\/9thclass.deltapublications.in\/?page_id=3643"},"modified":"2025-11-21T10:02:34","modified_gmt":"2025-11-21T10:02:34","slug":"s-3-b-what-is-an-atom","status":"publish","type":"page","link":"https:\/\/9thclass.deltapublications.in\/index.php\/s-3-b-what-is-an-atom\/","title":{"rendered":"S-3.b What Is An Atom?"},"content":{"rendered":"\n<h2 class=\"wp-block-heading has-text-align-center has-text-color\" style=\"color:#00056d;text-transform:uppercase\"><strong>What Is An Atom?<\/strong><\/h2>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div style=\"position: relative; width: 100%; height: 0; padding-top: 56.2500%;\n padding-bottom: 0; box-shadow: 0 2px 8px 0 rgba(63,69,81,0.16); margin-top: 1.6em; margin-bottom: 0.9em; overflow: hidden;\n border-radius: 8px; will-change: transform;\">\n  <iframe loading=\"lazy\" style=\"position: absolute; width: 100%; height: 100%; top: 0; left: 0; border: none; padding: 0;margin: 0;\"\n    src=\"https:\/\/www.canva.com\/design\/DAGvpyj2Bpc\/nkh3_57xnhKODKaHQ-bzfQ\/watch?embed\" allowfullscreen=\"allowfullscreen\" allow=\"fullscreen\">\n  <\/iframe>\n<\/div>\n<a href=\"https:&#x2F;&#x2F;www.canva.com&#x2F;design&#x2F;DAGvpyj2Bpc&#x2F;nkh3_57xnhKODKaHQ-bzfQ&#x2F;watch?utm_content=DAGvpyj2Bpc&amp;utm_campaign=designshare&amp;utm_medium=embeds&amp;utm_source=link\" target=\"_blank\" rel=\"noopener\">what is an atom<\/a> by Delta publications\n<\/div>\n<\/div>\n\n\n\n<p class=\"has-text-color has-huge-font-size\" style=\"color:#74008b\"><strong>Key Notes :-<\/strong><\/p>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-2a12625be2c71e425b42df642c79b302\" style=\"color:#000060;background-color:#dfc816\"><strong>Definition of an Atom<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"665\" height=\"667\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image.png\" alt=\"\" class=\"wp-image-15712\" style=\"width:275px;height:auto\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image.png 665w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-300x300.png 300w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-150x150.png 150w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-400x400.png 400w\" sizes=\"auto, (max-width: 665px) 100vw, 665px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-large-font-size\">An atom is the smallest unit of matter that retains the properties of an element. It cannot be broken down into simpler substances by chemical means.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-5e89d0cb98244d322f040d9331416c39\" style=\"color:#000060;background-color:#dfc816\"><strong>Structure of an Atom<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"760\" height=\"547\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-1.png\" alt=\"\" class=\"wp-image-15714\" style=\"width:367px;height:auto\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-1.png 760w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-1-300x216.png 300w\" sizes=\"auto, (max-width: 760px) 100vw, 760px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Atoms consist of three fundamental particles: <strong>protons<\/strong>, <strong>neutrons<\/strong>, and <strong>electrons<\/strong>.<\/li>\n\n\n\n<li><strong>Protons<\/strong> (positively charged) and <strong>neutrons<\/strong> (neutral) are located in the <strong>nucleus<\/strong>, which is the dense central part of the atom.<\/li>\n\n\n\n<li><strong>Electrons<\/strong> (negatively charged) orbit the nucleus in regions called <strong>electron shells<\/strong> or <strong>energy levels<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-e1d0554ea8dd99a85aca4ebe47dbf05c\" style=\"color:#000060;background-color:#dfc816\"><strong>Size of an Atom<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"602\" height=\"265\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-2.png\" alt=\"\" class=\"wp-image-15715\" style=\"width:516px;height:auto\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-2.png 602w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-2-300x132.png 300w\" sizes=\"auto, (max-width: 602px) 100vw, 602px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Atoms are extremely small, with diameters typically around <strong>0.1 to 0.5 nanometers<\/strong> (1 nanometer = 10<sup>\u22129<\/sup>).<\/li>\n\n\n\n<li>The nucleus is even smaller but contains nearly all of the atom&#8217;s mass.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-c4140059cf37ddcf48f768d2d7dd0766\" style=\"color:#000060;background-color:#dfc816\"><strong>Atomic Number and Mass Number<\/strong>:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"512\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-3-1024x512.png\" alt=\"\" class=\"wp-image-15716\" style=\"width:452px;height:auto\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-3-1024x512.png 1024w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-3-300x150.png 300w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-3-768x384.png 768w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2024\/11\/image-3.png 1399w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>The <strong>atomic number<\/strong> represents the number of <strong>protons<\/strong> in an atom and determines the element.<\/li>\n\n\n\n<li>The <strong>mass number<\/strong> is the total number of <strong>protons and neutrons<\/strong> in the nucleus.<\/li>\n\n\n\n<li>Atoms of the same element can have different numbers of neutrons; these are called <strong>isotopes<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-a27ddc7e6640917948109c9e016dd53a\" style=\"color:#000060;background-color:#dfc816\"><strong>Electrons and Energy Levels<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Electrons are arranged in <strong>energy levels (shells)<\/strong> around the nucleus.<\/li>\n\n\n\n<li>The first energy level can hold up to <strong>2 electrons<\/strong>, the second up to <strong>8 electrons<\/strong>, and so on.<\/li>\n\n\n\n<li>The arrangement of electrons determines an atom&#8217;s <strong>chemical properties<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-7b77988fc34795b59f430c632bfef847\" style=\"color:#000060;background-color:#dfc816\"><strong>Neutral Atoms vs. Ions<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>In a <strong>neutral atom<\/strong>, the number of protons equals the number of electrons.<\/li>\n\n\n\n<li>If an atom gains or loses electrons, it becomes an <strong>ion<\/strong>. A positively charged ion is a <strong>cation<\/strong>, and a negatively charged ion is an <strong>anion<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-8aa392c721466a71cde5f4c3250f21a0\" style=\"color:#000060;background-color:#dfc816\"><strong>Discovery of the Atom<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>The concept of the atom was first proposed by <strong>Democritus<\/strong>, a Greek philosopher, around 400 BCE.<\/li>\n\n\n\n<li>The modern understanding of atomic structure was developed through experiments by scientists like <strong>John Dalton<\/strong>, <strong>J.J. Thomson<\/strong>, <strong>Ernest Rutherford<\/strong>, and <strong>Niels Bohr<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center has-text-color has-background has-link-color has-large-font-size wp-elements-f70deb38bc126fc63a98570296dd0b1d\" style=\"color:#000060;background-color:#dfc816\"><strong>Importance of Atoms<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list has-large-font-size\">\n<li>Atoms are the <strong>building blocks<\/strong> of all matter. Everything around us, from the air we breathe to the materials we use, is composed of atoms.<\/li>\n\n\n\n<li>Understanding atomic structure is fundamental to chemistry and physics, influencing fields like <strong>medicine<\/strong>, <strong>electronics<\/strong>, and <strong>materials science<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-color has-large-font-size\" style=\"color:#d90000\">Let&#8217;s practice!<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/75920\/931\/895\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-2-11.png\" alt=\"\" class=\"wp-image-6370\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-2-11.png 500w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-2-11-300x300.png 300w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-2-11-150x150.png 150w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/wordwall.net\/play\/58850\/292\/434\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"500\" src=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-1-12.png\" alt=\"\" class=\"wp-image-6371\" srcset=\"https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-1-12.png 500w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-1-12-300x300.png 300w, https:\/\/9thclass.deltapublications.in\/wp-content\/uploads\/2023\/03\/Worksheet-1-1-1-12-150x150.png 150w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>What Is An Atom? what is an atom by Delta publications Key Notes :- Definition of an Atom: Structure of an Atom: Size of an Atom: Atomic Number and Mass Number: Electrons and Energy Levels: Neutral Atoms vs. Ions: Discovery of the Atom: Importance of Atoms: Let&#8217;s practice!<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-3643","page","type-page","status-publish","hentry","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/comments?post=3643"}],"version-history":[{"count":20,"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3643\/revisions"}],"predecessor-version":[{"id":18269,"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/pages\/3643\/revisions\/18269"}],"wp:attachment":[{"href":"https:\/\/9thclass.deltapublications.in\/index.php\/wp-json\/wp\/v2\/media?parent=3643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}