lesson for isotopes

1. ISOTOPES
& The Periodic table
LEARNING OBJECTIVES:
Define Isotopes
Compare the properties of isotopes
Research on some applications of isotopes
Describe the positions of different elements on the periodic table.
https://www.youtube.com/watch?v=fLSfgNxoVGk

2. Alkali metals
• Alkaline metals : belong to the first Vertical column - GROUP 1
• Carefully observe the video
• https://www.youtube.com/watch?v=6ZY6d6jrq-0
• Predict some general properties of this Group
• How many valence electrons do they have? ____________
• Whom do they quickly react with? _____________
• As we move down a group it is seen that the
_____________________ increases

3. Alkaline earth metals
• Alkaline metals : belong to the first Vertical column - GROUP 2
Carefully observe the video
• https://www.youtube.com/watch?v=Q_8OVgEDu8s
• Predict some general properties of this Group
• How many valence electrons do they have? ____________
• Are they more reactive than Alkali metals? _____________
• As we move down a group it is seen that the
_____________________ increases

4. Noble gases
• Noble gases: belong to the last Vertical column - GROUP 8 Carefully
observe the video
• https://www.youtube.com/watch?v=g3xBsqAU39c
• Predict some general properties of this Group
• How many valence electrons do they have? ____________
• Are they reactive ? _____________

5. Properties of a Group
• All elements in the same group have same outer electronic configurations
so have similar chemical properties.
• They all have the same valency.
• If the properties of 1 element in the group is known , then we can predict
the properties of all other elements on the group.
• As we move down a group , the no of electronic shells increases.
Properties of a Period
• On moving from left to right of the period all elements have
increasing atomic numbers .
• Electrons are added to the same shell.
• On moving from left to right of the period, the metallic properties
decrease and non-metallic properties increase.

6. General properties
• Properties of elements repeat at regular intervals
• Hence called periodic table.
• The elements are arranged on the basis of their increasing atomic
numbers.
• Metals ( alkali and alkaline earth metals ) are placed on the extreme
left of the table.
• Transition metals are placed at the center of the table.
• Non-metals are placed on the right hand corner of the table.
• Noble gases are placed to the extreme right of the table.

7. Metalloids
• Metalloids: show prpoperties of both metals and non metals
• https://www.youtube.com/watch?v=TcvMroyYaW0
• Predict some general properties of this Group
• How many valence electrons do they have? ____________
• Are they reactive ? _____________

8. Halogens
• Halogens: belong to the second last Vertical column - GROUP 7
Carefully observe the video
• https://www.youtube.com/watch?v=HT1zAPQIBAQ
• https://www.youtube.com/watch?v=u2ogMUDBaf4
• Predict some general properties of this Group
• How many valence electrons do they have? ____________
• How many electrons do they need to become stable ? ____________
• Are they reactive ? _____________