Making In Order
Chapter Name : Periodic Classification Of Elements |
Sub Topic Code : 102_10_05_02_02 |
Topic Name : Making In Order |
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Sub Topic Name : Achievements Of Mendeleev's Periodic Table |
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Introduction
· Mendeleev left some gaps in his table. He predicted these gaps are for elements which had not been discovered at that time.
· He named these elements not yet discovered by prefixing a Sanskrit numeral Eka to name of preceding element in the same group.
· Mendeleev also predicted the properties of these elements. Later after discovery the many properties were found to be nearly same.
· One of the advantages of Mendeleev’s table was that element discovered later could be added to the table without disturbing the existing order.
· The predictions came true and these facts made Chemists accept Mendeleev as originator of the concept of the Periodic Table.
Pre-Requisites:
Periodic table
Activity:
Different make up different substances e.g. Water is made of hydrogen and oxygen.
Real Life Question:
How were different elements identified?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Elements | A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Elements are divided into metals, metalloids, and non-metals. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| A racing track | Center of the track is the nucleus having protons and neutrons, the running tracks are the orbits and the racers are the electrons. |
Real life uses :
For the identification and grouping and classification of elements.
Places to visit :
Laboratory.
Practical examples around us
| Examples | Explainations |
|---|---|
| Water | Water is made of hydrogen and oxygen. |
What you learn in Theory:
· Mendeleev left some gaps in his table.
He predicted these gaps are for elements which had not been discovered at that time.
· He named these elements not yet discovered by prefixing a Sanskrit numeral
Eka to name of preceding element in the same group.
· Mendeleev also predicted the properties of these elements. Later after discovering the many properties were found to be nearly same.
· One of the advantages of Mendeleev’s table was that element discovered later could be added to the table without disturbing the existing order.
The predictions came true and these facts made Chemists accept Mendeleev as originator of the concept of the Periodic Table.
What you learn in Practice:
For classification of elements.