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Metallic and nonmetallic property
CHEMISTRY - Secondary 2
In This part we will study:
 Metallic and nonmetallic property:
• At the beginning of the nineteenth century "Berzelius" was the first scientist who classified elements into two main groups (metals and nonmetals), according to their physical properties. Indeed that was before knowing anything about atomic structure.
• This is an old classification which is still currently in use, although there are no boundaries between their properties in the periodic table.
• With the development of our concept about the electronic structure of atoms, we can differentiate between metals and nonmetals. In addition to, a third group of elements known as metalloids.

• The metalloids are characterized by the following properties:
 They have the metallic appearance and the most properties of nonmetals.
Their electronegativity is intermediate between metals and nonmetals.
 Their electric conductivity is less than that of metals, but more than that of nonmetals.
 They are used in manufacturing some electronic instruments parts, such as transistors, as they are semiconductors.

The graduation of metallic and nonmetallic property in the periodic table
The graduation of metallic and nonmetallic property in the periodic table
In the same group:
The metallic character increases (The nonmetallic character decreases) with the increase in the atomic number as we go down the group, due to their large atomic radius and the low ionization potential and electron affinity.

In the same period:
The period begins by the strongest metal in group 1A, then the metallic property decreases gradually by increasing the atomic number across the period till we reach the metalloids.
To the right of the metalloids begins the nonmetallic property.
The period ends by the elements of the highest nonmetallic property in group 7A

Application The graduation of metallic and nonmetallic property in the third period.
• The following figure expresses the graduation of metallic and nonmetallic property in the third period.
• It is clear that by increasing the atomic number, the metallic character decreases and the nonmetallic character increases.

Best wishes to you
Mr.Ahmed Elbasha

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