Group-1 Elements: The Alkali Metals
Chapter Name : The S- Block Elements |
Sub Topic Code : 102_11_10_02_05 |
Topic Name : Group-1 Elements: The Alkali Metals |
|
Sub Topic Name : Physical Properties |
|
Introduction
• Group 1 of the Periodic Table consists of the elements: lithium, sodium, potassium, rubidium, cesium and francium. • They are collectively known as the alkali metals. • These are so called because they form hydroxides on reaction with water which are strongly alkaline in nature. • All the alkali metals are silvery white, soft and light metals. • Because of their large size, these elements have low density which increases down the group from Li to Cs. • However potassium is lighter than sodium. • The melting and boiling points of the alkali metals are low indicating weak metallic bonding due to the presence of only a single valence electron in them. • The alkali metals and their salts impart a unique color to an oxidizing flame.
Pre-Requisites:
Alkali metals, periodic table, s-block
Activity:
Nerve impulse conduction, Sodium is a primary ingredient of common salt.
Real Life Question:
How do nerve impulses work?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Alkali metals | • Group 1 elements. |
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 :
Nerve impulse conduction.
Places to visit :
Kitchen.
Practical examples around us
| Examples | Explainations |
|---|---|
| salt | Salt contains sodium. |
What you learn in Theory:
• All the alkali metals are silvery white, soft and light metals. • Because of their large size, these elements have low density which increases down the group from Li to Cs. • However potassium is lighter than sodium. • The melting and boiling points of the alkali metals are low indicating weak metallic bonding due to the presence of only a single valence electron in them. • The alkali metals and their salts impart a unique color to an oxidizing flame.
What you learn in Practice:
• All the alkali metals are silvery white, soft and light metals. • Because of their large size, these elements have low density which increases down the group from Li to Cs. • However potassium is lighter than sodium. • The melting and boiling points of the alkali metals are low indicating weak metallic bonding due to the presence of only a single valence electron in them. • The alkali metals and their salts impart a unique color to an oxidizing flame.