MODERN PERIODIC TABLE

-

  • It was discovered by Moseley. 
  •  It was based on atomic number. 
Modern periodic law :- 

The physical and chemical properties of elements are periodic function of their atomic number . That is if the elements are arranged in the increasing order of their atomic number . Then the similar properties of element are repeated after a regular intervals, i.e. 2,8,8,18,18,32.

Characteristics of modern periodic table :-
  • Elements are classified according to their atomic number. 
  • Ther periods e are 9 vertical groups and 7 horizontal periods
  • The groups upto VII - 7 groups , VIII - 1group, '0' - 1 group
  • '0' - group elements are called Inert gas or Noble gas group. This group was discovered by Ramsay. 


Comments

Post a Comment

Popular posts from this blog

LONG FORM OF PERIODIC TABLE

-
Image
In Long form periodic table elements have been arranged in the increasing order of their atomic mass and also based on electronic configuration.  This periodic table consists of (i) 7 horizontal rows known as periods.  (ii) 18 vertical columns known as groups.  (iii) 4 blocks Periods There are seven periods in the periodic table. The number of elements in each period corresponds to number of electrons in different major energy levels. Each period starts with a new principle quantum number.  The horizontal rows from left to right in the periodic table are called periods.  There are 7 horizontal rows. So there are 7 periods.  The number of elements in each period corresponds to number of electron in different energy levels.  1 st  PERIOD This period corresponds to first energy level, whose capacity is two electrons. So there are two elements present in the 1st period. They are H(1s 1 ) , He (1s 2 ) . It is the shortest period.  2nd  PERIOD...
Read more

SYMBOLS OF ELEMENTS

-
Image
  SYMBOL  :- It is defined as an abbreviation (short hand sign) for the full name of an element.  Ex :- Hydrogen is represented by the symbol 'H' Oxygen is represented by the symbol 'O'  The first letter of the symbol is always capital while the second one is always small.  Ex :- Symbol of Nickel is 'Ni' not 'NI'.  List of some Elements   1- Hydrogen                     H 2- Helium                          He 3- Lithium                         Li 4- Beryllium                     Be 5- Boron                             B 6- Carbon                           C 7- Nitrogen ...
Read more

BLOCKS OF ELEMENTS

-
Image
  Periodic table is divide into 4  blocks known as S, p, d, f  blocks. The classification of the elements depends upon the type of sub-shell in which last electron of the element enters.  S - Block elements   The element in which last electron enters into s - subshell  are called s - block element.  The general electronic configuration of s - block elements are  ns 1-2   .  The s - block elements are present in the left side of the periodic table.  Group 1 and Group 2 elements as well as Helium of zero group are known as the s - block elements. All s - block elements are normal elements. Characteristics of s - block elements (i) The elements have low ionization energy.  (ii) They are soft metal having low melting and boiling point.  (iii) They are highly reactive.  (iv) They are good reducing agents.  (v) They give to the flame.  p - block elements The elements in which last electrons enters into p - subshel...
Read more