What are the Transition Elements ?

The periodic table

It consists of 4-blocks : s-block , d-block ,p-block and f-block as in the following figure

Transition elements

The element which (d) or (f) sublevels are occupied by electrons but not completely filled with electrons either in atomic sate or in  one of its oxidation states.

Transition elements are divided into two main types which are:
   1-Main transition elements       2-Inner transition elements 

Main transition elements 

It consists of ten vertical columns (8 groups)

• These columns from the left to the right of the periodic table are groups (3B, 4B, 5B, 6B, 7B ,eight group (VIII) which include three vertical columns, groups (8, 9, 10)then IB,IIB
• Group8 (VIII) differ from other groups (B) in which these elements are similar horizontally more than the elements below in the same column
• Then group (8) is followed by groups 1B (11) and 2B (12)
• It includes more than 60 elements  (more than half the number of known elements) 
• They occupy the middle block of the table between s-block and p-block 

Main transition elements can be divided into four horizontal series

     1)First transition series

• The 3d is filled successively
• Located in in the 4th period
• It has (10) elements starts of scandium 18Ar ,4S² , 3d¹ and ends and ends in Zinc element (30Zn) 18Ar ,4S² , 3d¹⁰
  
  

  2)Second transition series

• The 4d is filled with electrons successively
• Located in in the 5th period
• It has (10) elements starts of yttrium(39Y): 36Kr,5S² , 4d¹ and ends in Cadmium(48Cd): 36Kr,5S² , 4d¹⁰
  

  3)Third Transition series:

• The 5d is filled successively
• Located in :in 6th period
• It has (10) elements starts of Lanthanum 57La [54Xe] 6s² , 5d¹ , ends in mercury (80Hg) [54Xe] 6s² , 5d¹⁰

    4)Fourth transition series

• The 6d is filled successively
• Located in :in 7th period

The Most Abundant Elements In Earth’s Crust:

Oxygen : 46.1% –Silicon : 28.2%

Aluminium :8.23% – Iron :5.63%

Calcium : 4.15%

Quiz1:Transition Elements:

quiz