CLASSIFICATION OF PERIODIC TABLE BASED UPON BLOCK

 

 CLASSIFICATION OF PERIODIC TABLE BASED UPON BLOCK

·        Introduction

·        Classification of periodic table

·        Distribution of electrons in shells

·        Characteristics of modern periodic table

·        Physical Properties of modern periodic table









a.Introduction:              

·       At present, there are 118 elements in the modern periodic table.

·       Out of 118 elements ,92 elements are recognised with atomic number 1 to 92 which are found in nature.

·       Hence the modern periodic table was developed by Henry Moseley, in 1913.

·       He studied the characteristic X- rays spectra of several elements by bombarding them with high energy electrons and observed a linear corelation between atomic number and the frequency of X-RAYS EMITTED .

·       The MODERN PERIODIC LAW states that, “ the physical and chemical properties of the element are the periodic functions of their atomic number.”

·       The last shell of the atom is also known as   VALENCE SHELL.

·       The 118 element in the Periodic table is classified into four block as per their electronic configuration (last subshell of valence shell) .

                      i.       S-Block Element
                    ii.      P-Block Element
                 iii.       D-Block Element 
iv.  F-Block Element

PERIODIC TABLE


c.DISTRIBUTION OF ELECTRON IN SHELL:

  •        s- block element
  •        p- block element
  •        d- block element
  •        f-block element

 

s- BLOCK ELEMENTS:

 

  •          The last electron enters into s subshell of any shell
  •    ( K,L,M,…)

 

  •         ns1-2

(n=1,2,3,…7)


                                                                              

p- BLOCK ELEMENTS:


  •           The last electron enters into p subshell of any shell

( K,L,M,N…)

 

  •         np1-6

(n=1,2,3,…7)



d- BLOCK ELEMENT:


  •         The last electron enters into d subshell of any shell

( K,L,M,N…)

 

  •          nd1-10

(n=1,2,3,…7)



f-BLOCK ELEMENT:


  •        The last electron enters into f subshell of any shell

( K,L,M,N…)

 

  •         nd1-10 nf1-14

(n=1,2,3,…7)









SOME PROPERTIES OF MODERN PERIODIC TABLE:



CHARACTERISTICS OF MODERN PERIODIC TABLE.

·          The modern periodic table is divided into mainly two categories. 

          i.   Vertical column-Periods (1-7) 

               ii.    Horizontal rows- Group (1-18

·        The element of same groups have same valence shell configurations.

·        In periods, the number of valence shell remains the same, however the number of electrons increase from right.

·        The group is mainly classified into 3 

   * Main group – (1, 2, 13 -17)

   * Transition element – (3 - 12)

    * Noble gas – (18)








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