Group 13 Elements: The Boron Family
Chapter Name : The P- Block Elements |
Sub Topic Code : 102_11_11_02_02 |
Topic Name : Group 13 Elements: The Boron Family |
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Sub Topic Name : Atomic Radii |
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Introduction
• On moving down the group, for each successive member one extra shell of electrons is added and, therefore, atomic radius is expected to increase. • However, a deviation can be seen in group 13 elements. • Atomic radius of Ga is less than that of Al. • This can be understood from the variation in the inner core of the electronic configuration. • The presence of additional 10 d-electrons offer only poor screening effect for the outer electrons from the increased nuclear charge in gallium. • Consequently, the atomic radius of gallium (135 pm) is less than that of aluminium (143 pm).
Pre-Requisites:
Elements, periodic table, Group, atomic radii
Activity:
• Group 13 has aluminium, boron which are important industrial elements.
Real Life Question:
What is aluminium used for?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| P block elements | Have the last electron in the outermost p orbital. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Periodic table | Look at Groups 13 in the periodic table. |
Real life uses :
• Aluminium is a metal used to make utensils, aircraft parts. Etc.
Places to visit :
Chemistry lab.
Practical examples around us
| Examples | Explainations |
|---|---|
| Aluminium | Aluminium belongs to the group 13 elements. |
What you learn in Theory:
• On moving down the group, for each successive member one extra shell of electrons is added and, therefore, atomic radius is expected to increase. • However, a deviation can be seen in group 13 elements. • Atomic radius of Ga is less than that of Al. • This can be understood from the variation in the inner core of the electronic configuration. • The presence of additional 10 d-electrons offer only poor screening effect for the outer electrons from the increased nuclear charge in gallium. • Consequently, the atomic radius of gallium (135 pm) is less than that of aluminium (143 pm).
What you learn in Practice:
• Group 13 has aluminium, boron which are important industrial elements.