Anomalous Behavior Of Beryllium
Chapter Name : The S- Block Elements |
Sub Topic Code : 102_11_10_09_02 |
Topic Name : Anomalous Behavior Of Beryllium |
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Sub Topic Name : Diagonal Relationship Between Beryllium And Aluminum |
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Introduction
• The ionic radius of Be2+ is estimated to be 31 pm; the charge/radius ratio is nearly the same as that of the Al3+ ion. • Hence beryllium resembles aluminium in some ways. • Like aluminium, beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal. • Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion, [Be (OH) 4]2– just as aluminium hydroxide gives aluminate ion, [Al (OH) 4]–. • The chlorides of both beryllium and aluminium have Cl– bridged chloride structure in vapour phase. • Both the chlorides are soluble in organic solvents and are strong Lewis acids. • They are used as Friedel Craft catalysts. • Beryllium and Aluminium ions have strong tendency to form complexes, BeF42–, AlF6 3–.
Pre-Requisites:
Alkali earth metals, elements, periodic table
Activity:
Beryllium alloys are used in the aerospace industry as light-weight materials for high performance aircraft, satellites and spacecraft.
Real Life Question:
What type of alloy does light weight aircraft has?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| amphoteric | • Acts as both an acid and a base. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Periodic table | Look at the elements present in the group 2 of the periodic table. |
Real life uses :
Beryllium alloys are used in the aerospace industry as light-weight materials for high performance aircraft, satellites and spacecraft.
Places to visit :
Airport, pathology center.
Practical examples around us
| Examples | Explainations |
|---|---|
| Light weight aircraft | These use beryllium alloys. |
What you learn in Theory:
• The ionic radius of Be2+ is estimated to be 31 pm; the charge/radius ratio is nearly the same as that of the Al3+ ion. • Hence beryllium resembles aluminium in some ways. • Like aluminium, beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal. • Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion, [Be(OH)4]2– just as aluminium hydroxide gives aluminate ion, [Al(OH)4]–. • The chlorides of both beryllium and aluminium have Cl– bridged chloride structure in vapour phase. • Both the chlorides are soluble in organic solvents and are strong Lewis acids. • They are used as Friedel Craft catalysts. • Beryllium and Aluminium ions have strong tendency to form complexes, BeF42–, AlF6 3–.
What you learn in Practice:
• Beryllium alloys are used in the aerospace industry as light-weight materials for high performance aircraft, satellites and spacecraft.