Page 1 - 3. Lesson Note Ch-5 TRENDS IN THE PROPERTIES
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SAI International School
Class-X
Subject - Chemistry
Topic- Periodic Classification
Sub topic - Modern Periodic Classification
(Characteristics of Periods & groups)
Lesson Notes
Mind map for Modern Periodic Table
[Elements are arranged according to the increasing order of atomic number.]
Periods Groups
1. 7 Periods 1. 18 groups
2. Same no. of shells 2. No. of shells increase
consecutively down the group.
3. Valence electrons 3. Valence electrons remain the
increase consecutively same down a group.
from left to right.
4. Chemical properties 4. Chemical properties
change gradually. remain the same.
5. Atomic size decreases 5. Atomic size increases down
from left to right. the Group.
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