D and F Block Elements

What are the d- and f-block Elements?

The elements present in the middle of the periodic table from Group 3 to 12 are called d-block elements. The name d- blocks because the last electron enters into the d-orbital of the penultimate shell.

These are often called transition elements because their characters lie between highly reactive metallic elements of s-block and nonmetallic elements of p-block elements. There are four series in the d block corresponding to the filling up of 3d, 4d, 5d or 6d orbitals.

  • First transition series or 3d series ( Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn)
  • Second transition series or 4d series (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd)
  • Third transition series or 5d series (La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg)
  • Fourth transition series or 6d series- incomplete.

On the other hand,

f block elements are found outside at the bottom of the periodic table. The name f- blocks because the last electron enters into the f-orbital of the anti-penultimate shell.

These are also called inner transition elements. There are 2 series in the f block, corresponding to the filling up of 4f and 5f orbitals.

  • Lanthanide series or 4f series (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb)
  • Actinide series of 5f series ( Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, Mo)

D and F Block Elements

The brief study on d-block or transition elements

  • Typically, the transition elements have an incompletely filled d-orbital. So that  Zn, Cd, and Hg are not regarded as transition elements because they have completely filled d-orbitals (nd10 ), compounds of these elements are not typical and show differences from other elements.
  • The general electronic configuration of d-block element is (n-1)d1-10 ns2

Some important Topics of d-block Elements

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Brief Study on f-Block or Inner-Transition Elements

  • In the f-block elements or inner-transition elements the electron enters into the anti-penultimate energy level i.e (n-2) energy level.
  • The general electronic configuration of f-block element is (n-2)f1-14 (n-1)d0-1 ns2

On the basis of the entrance of the last electron either into 4 f-orbital or 5 f-orbital, these elements are classified into two categories called lanthanides and actinides respectively.

anti-penultimate energy level

Lanthanides:

The name lanthanides comes from lanthanum (La, Z=57) because these elements are closely related to lanthanum. This series included 14 elements from cerium (Z=58) to lutetium (Z=71). 

Find the important features of lanthanides elements

  • Electronic configuration of lanthanides

The general electronic configuration of lanthanide is [Xe] 4f1-14  5d0-1 6s2

Element Symbol Electronic configuration
Cerium Ce [Xe] 6s25d14f1
Praseodymium Pr [Xe] 6s24f3
Neodymium Nd [Xe] 6s24f4
Promethium Pm [Xe] 6s24f5
Samarium Sm [Xe] 6s24f6
Europium Eu [Xe] 6s24f7
Gadolinium Gd [Xe] 6s25d14f7
Terbium Tb [Xe] 6s24f9
Dysprosium Dy [Xe] 6s24f10
Holmium Ho [Xe] 6s24f11
Erbium Er [Xe] 6s24f12
Thulium Tm [Xe] 6s24f13
Ytterbium Yb [Xe] 6s24f14
Lutetium Lu [Xe] 6s25d14f14

Find the important features of lanthanides elements

  • Electronic configuration of lanthanides

The general electronic configuration of lanthanide is [Rn] 5f1-14  6d0-1 7s2

Element Symbol Electronic configuration
Thorium Th [Rn] 7s26d2
Protactinium Pa [Rn] 7s26d15f2
Uranium U [Rn] 7s26d15f3
Neptunium Np [Rn] 7s26d15f4
Plutonium Pu [Rn] 7s25f6
Americium Am [Rn] 7s25f7
Curium Cm [Rn] 7s26d15f7
Berkelium Bk [Rn] 7s25f9
Californium Cf [Rn] 7s25f10 
Einsteinium Es [Rn] 7s25f11
Fermium Fm [Rn] 7s25f12
Mendelevium Md [Rn] 7s25f13
Nobelium No [Rn] 7s25f14
Lawrencium Lr [Rn] 7s26d15f14 

Actinides:

The name actinide comes from actinium (La, Z=89) because these elements are closely related to actinium. This series included 14 elements, from thorium (Z=90) to lawrencium (Z=103).

Uses of Actinides

The actinides are radioactive in nature. These elements used as energy sources for example thorium is used in atomic reactors and  the treatment of cancer, uranium is used in nuclear fuel, its salts are used in glass industry, textile industry and medicines. Plutonium is used in nuclear fuel and atomic bombs.

Frequently Asked Questions – FAQs

What is the general configuration of d-block elements?

The general configuration of d-block elements is (n-1)d1-10 ns2.

How do the d-block elements differ from f-block elements?

In the d- blocks, the last electron enters into the d-orbital of the penultimate shell. In the f-block elements, the electron enters into the f-orbital of anti-penultimate shell.d-block elements show a variable oxidation state, while most f-blocks show +3 oxidation state. Almost all d-blocks are stable, while more f-blocks are radioactive.

Why are 4f series called lanthanides?

The name lanthanides comes from lanthanum (La, Z=57) because these elements are closely related to lanthanum. This series included 14 elements from cerium (Z=58) to lutetium (Z=71).

What are the characteristics of d-block elements?

The general characteristics of d-block elements are

  • All the transition elements are metals, so they are good conductors of electricity and heat, have a metallic lustre, ductile, and form alloys with other elements.
  • They show variable oxidation states.
  • They form complex compounds.
  • They show catalytic properties.
  • Have high melting and boiling points
  • They show colour compounds.
  • Show magnetic properties.

What are the catalytic properties of transition elements?

Transition elements show catalytic properties because of the presence of vacant d-orbitals, the tendency to exhibit variable oxidation states, the tendency to form reaction intermediates with reactants and the presence of defects in their crystal lattices. Example Pt, Fe, V2O5, Ni etc, are the most common transition metals and its compounds show good catalytic activity.

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