d block and f block elements | Google Science

We all know that the long form of the periodic table has been divided into four blocks.They are named as s block,p block, d block and f block. An element in a particular block depends upon its valence shell configuration.Each group is an independent group.The d block elements are known as transition elements.These are placed in 3-12 groups of the periodic table.

A further look at the periodic table reveals that both the periods of f block are basically apart of the elements belonging to group 3. The first series of elements (known as lanthanoids follow lanthanum (La) of d block. Similarly, the elements included in the series known as actinoids follow actinium (Ac) of d block.

d block and f block

D block is present in the centre of the periodic table and has metals of s-block on the left and nonmetals of p-block on the right. This is true for all the elements included in the d block except for those present in group 12. These are Zn, Cd and Hg. They have completely filled d-orbitals (do configuration). They differ in many characteristics as compared to rest of the elements belonging to the same period. But being end elements, they have been retained in the d block.

d block f block elements

Similarly, the elements present at the bottom of the table are included in the f block. There are two series, each having fourteen elements because f -subshell can have a maximum of fourteen electrons.In a case of the d- subshell is partly filled, the elements are called as d block elements; and when the f-subshell is partly filled, the elements are called as f block elements.

What are d Block Elements?

Strictly speaking,

A transition element is defined as the one which has incompletely filled d-orbitals in its ground state or in any of its oxidation states. OR

It is defined as the elements of those atoms in a ground state or ion in one of common oxidation states, has partially filled d subshell i.e having electrons lie between 1 to 9.

d block f block elements

There are four transition series in the d block starting with electronic configuration, 3d, 4d, 5d and 6d respectively.

First transition series or 3d-series

Elements from atomic number 21 to 30 are included in this series. There are 10 elements in this series viz., Sc (21), Ti(22), V (23), Cr (24), Mn(25), Fe(26), Co (27), Ni(28), Cu (29) and Zn(30) corresponding to the filling of 3d-subshell.

Second transition series or 4d-series

Elements from atomic number 39 to 48 are included in this series. There are 10 elements in this series viz., Y (39), Zr (40), Nb (41), Mo (42), Tc (43), Ru (44), Rh (45), Pd(46), Ag (47) and Cd (48) corresponding to the filling of 4d-subshell.

Third transition series or 5d-series

Elements with atomic number 57 and from 72 to 80 are included in this series. There are 10 elements in this series viz., La (57), Hf (72), Ta (73), W(74), Re (75), Os (76), Ir (77), Pt (78), Au (79) and Hg (80) corresponding to the filling of |-subshell. Elements from 58 to 71 are f block elements because, after the filling of one electron in 5d-subshell in La (57), 4f subshell starts filling with elements having atomic numbers from 58 to 71. These are called Lanthanoids because they follow lanthanum (La) with Z = 57.

Fourth transition series or 6d-series

Elements with atomic number 89 and from 104 to 112 are included in this series. These are : Ac(89), Rf (104), Db(105), Sg(106). Bh(107), Hs(108), Mt(109), Ds(110), Rg(111), Uub(1,12). The characteristics of some of these elements are still to be established. Therefore, enough information is not known about them. Elements from 90 to 103 are present in f block (filling takes place in 5f sub-shell). These are known as Actinoids because they follow actinium (Ac) with Z = 89.

Electronic Configuration of d block elements

The general valence shell configurations of transition elements is  (n-1)d1–10.ns1-2.

Refer to the following video for electronic configuration of d block elements

Depth knowledge of transition metals under following subtopics:

 

What are F Block Elements?

These are known as inner transition elements. In a case of f-block elements, the incomplete subshells are (n-2) f and (n-1) d subshells.In other words, the number of electrons in the outermost shell (n) of the transition elements remains same and hence these elements show nearly similar chemical properties (recall that chemical reactivity depends on the number of electrons in the outermost shell).

d block f block elements

Electronic Configuration of  F block elements

General electronic configuration of f – block elements is (n–2)f1–14(n–1)d0–1ns2

  • Lanthanides: [Xe]4f1–145d0–16s2
  • Actinides: [Rn]5f1–146d0–17s2

Refer to the following video for electronic configuration of d block elements

Depth knowledge of F block: Lanthanoids and actinoids under following subtopics:

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