General Characteristics Of The Compounds Of Alkali Metals
Chapter Name : The S- Block Elements |
Sub Topic Code : 102_11_10_03_02 |
Topic Name : General Characteristics Of The Compounds Of Alkali Metals |
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Sub Topic Name : Halides |
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Introduction
• The alkali metal halides, MX, (X=F,Cl,Br,I) are all high melting, colourless crystalline solids. • They can be prepared by the reaction of the appropriate oxide, hydroxide or carbonate with aqueous hydrohalic acid (HX). • All of these halides have high negative enthalpies of formation; the ?fH? values for fluorides become less negative as we go down the group, while the reverse is true for ?fH? for chlorides, bromides and iodides. For a given metal ?fH? always becomes less negative from fluoride to iodide. • All these halides are soluble in water.
Pre-Requisites:
Atom, compound, element, ionic
Activity:
Nerve impulse conduction, Sodium is a primary ingredient of common salt.
Real Life Question:
What is Sodium Chloride used for?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Alkali metals | Group 1 element. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| needle | Prick your finger with a needle lightly. See how the nerve impulse travels through and reaches the brain detecting pain. Sodium calcium and Potassium ions play a major role in nerve impulse conduction. |
Real life uses :
Use of common salt (sodium chloride) for cooking.
Places to visit :
Kitchen.
Practical examples around us
| Examples | Explainations |
|---|---|
| Sodium Chloride | Sodium Chloride is used as common salt for cooking. |
What you learn in Theory:
• The alkali metal halides, MX, (X=F,Cl,Br,I) are all high melting, colourless crystalline solids. • They can be prepared by the reaction of the appropriate oxide, hydroxide or carbonate with aqueous hydrohalic acid (HX). • All of these halides have high negative enthalpies of formation; the ?fH? values for fluorides become less negative as we go down the group, while the reverse is true for ?fH? for chlorides, bromides and iodides. For a given metal ?fH? always becomes less negative from fluoride to iodide. • All these halides are soluble in water.
What you learn in Practice:
All these halides are soluble in water.