Lesson 2 :Graduation of properties of elements in the modern periodic table( first part)

Graduation of properties of elements in the modern periodic table

lesson objectives

• At the end of the this lesson, the student should be able to:

1- Determine the properties of some elements by knowing their atomic numbers.

the chemical activity.

2- Identify metals, nonmetals and metalloids.

3- Compare between the properties of the groups and the periods of the periodic table.

4- Identify the polarity of some chemical compounds.

5- Identify the behavior of some metals of the chemical activity series with water.

6- Use tools and substances discovering the chemical properties of metals and nonmetals.

•  Bicometre = part of a million of a million of meter

•  1-Graduation of atomic size in the periodic table

1-The atomic size of the same period decreases by the increase of their atomic numbers.
Due to The increase of the attraction force between positive nucleus and the electrons in
the outermost energy level.

2-The atomic size of the same group increases by the increase of their atomic numbers due
to the increase of the number of the energy levels in the atoms.

• TO know more about graduation of atomic size in the periodic table, please visit these links:

   

   

   

   

  2-Graduation of electro  negativity in the periodic table.
  
  
  
                                                                           
  *By increasing the atomic number the electronegativity of elements of the same period increases, but it decreases in the same group.
  
  

  *TO know more about graduation of electronegativity in the periodic table, please visit these links:

  

   

   

   

   

   

   

   

   

  •  The polar compound is a covalent compound, the electronegativity difference between its elements is relatively high.
  
  
  

  • TO know more about graduation of The polar compound in the periodic table, please visit these links:

     

    

     

     

     

    
    

     

     

     

    

• Water compound

  
  

  1. When an oxygen atom combines with two hydrogen atoms to form a water molecule.

  2. In water molecule the ability of oxygen atom to attract two electrons of the covalent bond towards it is greater than the ability of hydrogen atom.

• TO know more about  water compound in the , please visit these links:

ammonia compound

1. When a nitrogen atom combines with three hydrogen atoms to form ammonia molecule

2. In ammonia molecule the ability of nitrogen atom to attract two electrons of the covalent bond towards it is greater than the ability of hydrogen atom.

• TO know more about graduation of ammonia compound in the periodic table, please visit these links: