{"id":1422,"date":"2025-05-14T17:47:55","date_gmt":"2025-05-14T12:17:55","guid":{"rendered":"https:\/\/www.chemtopper.com\/myblog\/?page_id=1422"},"modified":"2025-07-18T20:36:46","modified_gmt":"2025-07-18T15:06:46","slug":"periodic-trends-of-size-of-ions","status":"publish","type":"page","link":"https:\/\/www.chemtopper.com\/myblog\/periodic-trends-of-size-of-ions\/","title":{"rendered":"Periodic Trends of Size of Ions"},"content":{"rendered":"
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\"Periodic<\/a><\/figure>\n<\/div>\n\n\n

<\/p>\n\n\n\n

Understanding the Periodic Trends of Size of Ions: Cations vs. Anions<\/h2>\n\n\n\n

The size of ions differs significantly from that of their neutral atoms. Whether an atom loses or gains electrons<\/strong> directly affects its number of shells, electron-electron repulsion<\/strong>, and nuclear attraction<\/strong>\u2014all of which determine ionic radius<\/strong>.<\/p>\n\n\n\n

Let\u2019s break this down by looking at cations<\/strong> and anions<\/strong>.<\/p>\n\n\n\n

Cations: Smaller Than Neutral Atoms<\/h2>\n\n\n\n

Cations<\/strong> are positively charged ions<\/strong> formed when an atom loses one or more electrons<\/strong>. This electron loss leads to significant changes in atomic structure.<\/p>\n\n\n\n

Example 1: Potassium (K) \u2192 Potassium ion (K\u207a)<\/h4>\n\n\n\n

K (neutral atom):<\/strong>
Electron configuration: 1s\u00b2 2s\u00b2 2p\u2076 3s\u00b2 3p\u2076 4s\u00b9 <\/p>\n\n\n\n

Has 4 electron shells<\/strong> -19 protons and 19 electrons.<\/p>\n\n\n\n

K\u207a (cation):<\/strong>
Electron configuration: 1s\u00b2 2s\u00b2 2p\u2076 3s\u00b2 3p\u2076<\/p>\n\n\n\n

Now has 3 shells only<\/strong><\/p>\n\n\n\n

19 protons but only 18 electrons<\/p>\n\n\n\n

Example 2: Magnesium (Mg) \u2192 Magnesium ion (Mg\u00b2\u207a)<\/h2>\n\n\n\n

Mg:<\/strong> 3 shells, 12 protons, 12 electrons<\/p>\n\n\n\n

Mg\u00b2\u207a:<\/strong> 2 shells, 12 protons, 10 electrons<\/p>\n\n\n\n

Key Observations for Size of Cations:<\/h3>\n\n\n\n