A short notes on D block elements, Summaries of Earth science

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Electronic configuration : There are some exceptions in electronic configuration. In 3 d series :Cr 4s^1 3d^5 and Cu 4s^1 3d^ In 4 d series :Nb 5s^1 4d^4, Mo 5s^1 4d^5 similarly Tc,Ru,Rh,Pd,Ag In 5 d series :Pt 6s^1 5d^9 and Au 6s^1 5d^ In 6 d series :Rg 7s^1 6d^ Zn,Cd,Hg,Cn : (n-1)d^10 ns^ Because of their completely filled orbitals Zn,Cd,Hg are not regarded as transition elements. Also ions of a given d^n configuration (n=1-9) have similar magnetic & electronic properties. These elements exhibit certain characteristic properties : various oxidation states Formation of coloured ions Formation of complex compounds Physical properties: Transition elements have :High tensile strength,ductility,malleability,high thermal & electrical conductivity and metallic lustre also they are very hard,have low volatility,high melting and boiling points.(W,Mo,Cr ) have high M.P. Except Zn ,Cd,Hg & Mn transition elements have one or more typical metallic structures at normal temperature

Atomic and ionic sizes :

Coloured ions:

Catalytic property: Ability to adopt multiple oxdn states and to form complexes

vanadium (V) oxide in contact process Iron in habers process Nickel in catalytic hydrogenation

Interstitial compound formation

Compounds in which small atoms (H,C or N) are trapped inside crystal lattice of metals Non stoichiometric neither ionic nor covalent Tic,Mn4N ,Fe3H,VH0.56 and TiH1.7 are examples High melting points than pure metals Very hard ,some borides hardness is similar to diamonds

Retain metallic conductivity Chemically inert

Alloys:

Brass (copper-zinc)& Bronze( copper-tin)- Industrially imp. Chromium,vanadium,tungsten,molybdenum,manganese used in producing variety of steels&stainless steel.

Oxides and ox anions of metals:

Except scandium all form MO oxides.They are ionic.oxidation number of metal increases ionic character increases. In Mn,Mn2O7 is covalent green oil. CrO3&V2O5 shows acidic character.