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Metallic & nonmetallic property , Acidic & basic property in the periodic table

From Online Sciences - December 23, 2017

Metallic and nonmetallic property

At the beginning of the nineteenth century Berzelius was the first scientist who classified elements into two main group ( 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 them and their properties in the periodic table .

With the development of our concept about the electron structure of atoms , we can differentiate between metals and nonmetals , Additionally , there is a third group of elements known as metalloids .

Metals

Their valence shellgenerallyhas less than half its capacity of electrons , They have large atomic radius which leads to small values for ionization energy and electron affinity .

They are electropositive elements , due to their tendency to lose electrons of the valence shell and change into positive ions to reach the structure of the nearest noble gas .

They are good electric conductors , due to the mobility of their few valence electrons , which can transfer from one position to another in the metal structure .

Nonmetals

Their valence shellgenerallyhas more than half its capacity of electrons , They have small atomic radius which leads to high values for ionization energy and electron affinity .

They have small atomic radius which leads to high values for ionization energy and electron affinity , They are electronegative elements , due to their tendency to gain electrons to form negative ions that have the same electron structure of the nearest noble gas .

They do not conduct electricity ( electric insulators ) , because their valence electrons are strongly bound to the nucleus , Thus , it is difficult for these valence electrons to be transferred .

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 electronic instruments partssuch as transistorsas they are semiconductors .

Metalloids are a group of elements that has a metallic appearance and most of the properties of nonmetals which characterized by their electronegativity is intermediate between metals and nonmetals and their electric conductivity is less than that of metals , but more than that of nonmetals .

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 metals 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 .

Consequently : Cesium is considered the most active metal , because the metallic property increases at the same group by increasing the atomic number and it is placed at the bottom of the left hand side the table ( the lowest metal in ionization potential ) .

Fluorine is considered the most active nonmetal , because the nonmetallic property decreases at the same group by increasing the atomic number and it is placed at the top of the right side of the table ( the most electronegative nonmetal ) .

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 .

Acidic and basic property

When an element combines with oxygen forming a compound known as oxide , There are types of element oxides which are Acidic oxides , Basic oxides and Amphoteric oxides .

Acidic oxides

The nonmetallic oxides are named by acidic oxides , because :

They dissolve in water forming oxygenated acids .

CO2 ( g ) + H2O ( l ) H2CO3 ( aq )

SO3 ( g ) + H2O ( l ) H2SO4 ( aq )

Basic oxides

Amphoteric oxides

The graduation of acidic and basic property in the periodic table :

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