Number Of Atoms In A Unit cell
Chapter Name : The Solid State |
Sub Topic Code : 102_12_01_06_03 |
Topic Name : Number Of Atoms In A Unit cell |
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Sub Topic Name : Face Centered Cubic Unit Cell |
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Introduction
• A face centered unit cell contains 1 constituent particle at the centre of each face and 1 constituent particle at each of the corners. • Each corner of a face centered unit cell contains only 1/8th of a particle and each face contains ½ a particle. • The total number of constituent particles (say atom) in a face centered unit cell = 4. . .
Pre-Requisites:
• Crystal lattice and unit cell. • Types of unit cells.
Activity:
All properties of a solid depend on its structure. Try finding out which elements are made up of face centered unit cell.
Real Life Question:
How many atoms does one face centered unit cell contain?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Crystal lattice | It is a regular 3D arrangement of points in space. |
| Unit cell | It is the smallest portion of a crystal lattice. |
| Lattice point | Each point of a lattice is called a lattice point and contains 1 constituent particle (e.g. molecule, atom, and ion). |
| Face centered unit cell | A unit cell which contains 1 constituent particle at the centre of each face and 1 particle at each corner. |
Learning aids / Gadgets
| Gadgets | How it can be used |
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Practical examples around us
| Examples | Explainations |
|---|---|
| Silver element | It consists of a face centered unit cell structure. |
What you learn in Theory:
The number of atoms in a face centered unit cell.