Recent questions tagged the-d-block-and-f-block-elements

Description : Why are Ti+2 and other transition metals and their ions paramagnetic ?

Last Answer :  Ans: These ions have unpaired electrons in d- subshell. 

Description : Why do transition metals have higher I.E than s –block elements ?

Last Answer : Ans: It is due to smaller atomic size than s-block elements , effective nuclear charge is more , terefore I.E is high.

Description : Why is K2Cr2O7 generally preferred over Na2Cr2O7 in a volumetric analysis .Give reason .

Last Answer : Ans : It is because Na2Cr2O7 is hygroscopic in nature that is why it absorbs moisture from atmosphere , therefore its standard solution can not be prepared .

Description : Explain the following , giving reason . (a) Transition metal and many of their compounds show paramagnetic behavior (b) The enthalpy of atomisation of the transition metal is high . (c) The Transition metal generally form coloured compounds . 

Last Answer : Ans(a) It is due to unpaired electrons . (b) It is due to strong metallic bond and additional Covalent bonds due to presence of unpaired electron in d- orbitals (c) It is due to presence of unpaired electrons ,they undergo d-d transition . 

Description : Why are lanthanoid colored and paramagnetic L

Last Answer : Ans It is due to presence of unpaired electrons, they are paramagnetic and they absorb light From visible region and undergoes f-f transition and radiate complementary colour . 

Description : Why Mn+2 is more stable than Mn+3 but Fe +3 is more stable than Fe+2 ?

Last Answer : Ans Mn+2 has half filled d- orbital ,therefore it is more stable than Mn+3 Fe+3 has half filled d- orbital, therefore it is more stable than Fe +2 . 

Description : Why are transition metal fluorides are ionic in nature where as chlorides and bromides are covalent in nature . 

Last Answer : Ans - It is because of fluorine is most electronegative where as Cl and Br are less electro negative . Greater the difference in electro negativity more will be ionic character .

Description : Why is Cu+1 diamagnetic and Cu +2 paramagnetic ?

Last Answer : It is because Cu+ does not have unpaired electrons where as Cu+2 has unpaired electrons in d-sub cell . 

Description : Why do Zr and Hf show similar properties ?

Last Answer :  Ans It is due to similar ionic size which due to lanthanide contraction . 

Description : Why are Cr+ , Ag+ & Sc+3 Colour less ? 

Last Answer : Ans It is because they do not have unpaired electrons ,therefore can not under goes d-d transition .

Description : Why are transition metals and there compounds generally coloured ?

Last Answer : Ans It is due to present of unpaired electrons in transition metals and their ions , that is why they absorbed light from visible region and undergoes d-d transition and radiate complementary colour . 

Description : Why does V2O5 acts as catalyst ?

Last Answer : Ans : It is because V shows variable O.S . 

Description : What is an lanthanoid contraction ? What is its cause ? Give its consequences .

Last Answer : Ans The decrease in atomic and ionic size with increase in atomic no. in lanthanoid series is called lanthanoid contraction . The cause of lanthanoid contraction is poor shielding effect of d and f ... is close resemblance between elements of 4 d and 5 d transition series . due to similar ionic 

Description : Why Ce+3 Can be easily Oxidised to Ce+4 ?

Last Answer : Ans : It is because Ce+4 has stable electronic configuration . 

Description : Why do transition metals have high enthalpy of atomization ?

Last Answer :  Ans : it is due to strong metallic bonds and additional covalent bonds 

Description : What is the highest oxidation state shown by Cr. (24) , Mn(25) ?

Last Answer : Ans: Cr. Shows (+6) and Mn Shows (+7) Oxidation state .  

Description : Why are Zn , Cd , Hg are not regarded as transition metals ? 

Last Answer : Ans: It is because neither they nor their ions have incompletely filled d- orbitals . 

Description : What are d Block Elements ? 

Last Answer : Ans: Those elements in which d-orbital are progressively filled up are known as d-orbital.

Description : Application of d- & f- block elements

Last Answer : Application of d- & f- block elements:- 1. Iron and steel used in construction,as catalyst in Haber's process 2. CrO2 is used in magnetic tapes 3. Ni is in hydrogenation 4. W ( ... in contact process 9. Titanium is in nuclear reactions. 10. PdCl2 is in Wacker's process.