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The modern periodic table
CHEMISTRY - Secondary 2
In This part we will study:
The types of the periodic table elements
• It is possible to classify the elements in periodic table into four types, which are:
 Noble gases.
 The representative elements.
 The main transition elements.
 The inner transition elements.
 Noble gases
• They are the elements of the group zero "18" which is the last column of the p-block .

• They are characterized by having energy levels completely filled with electrons and their electronic configuration ends with np6 , except that of helium 2He which ends with 1s2

 The representative elements
• They are the elements of s and p-blocks, except that of group zero.

• They occupy the groups from 1A : 7A

• These elements are characterized by the complete filling of all the energy levels with electrons, except for the outermost level.
• They are active elements, because their outermost energy level tends to reach the completed electronic configuration similar to that of the nearest noble gas (ns2, np6) by gaining, losing or sharing electrons.

Examples
 The main transition elements
• They are the elements of the d-block.
• They are characterized by having energy levels completely filled by electrons, except the outermost two levels.

 The inner transition elements
• They are the elements of the f-block .
• They are characterized by having energy levels completely filled with electrons, except the outermost three levels.

The electronic configuration in the light of the modern periodic table

The periodic table shows a method to express the electronic configuration for the elements according to the nearest noble gas which precedes the element in the periodic table and this is considered the fourth method to the electronic configuration of elements which was mentioned before in the chapter one.
The following table shows the electronic configuration of illustrated elements in the previous periodic table:
The abnormality of electronic configuration for some elements of the periodic table
• By the same way the electronic configuration for Molybdenum (42Mo) and Gadolinium (64Gd)

• The following table represents the electronic configurations of the atoms of the element of the modern periodic table in their ground states:

Best wishes to you
Mr.Ahmed Elbasha

كيمياء الصف الثاني الثانوي لغات - الفصل الدراسي الاول
شرح كيمياء لغات تانية ثانوي - مستر احمد الباشا