Lanthanoids and actinoids.

What are Lanthanoid and actinoids. Give their positions in modern periodic table.

(a) Give three points of difference between lanthanoids and actinoids. (b) Give reason and select on one atom/ion which will exhibit asked property: (i) Sc^(3+) or Cr^(3+) (exhibit diamagnetic behaviour) (ii) Cr or Cu (high melting and boiling point)

What are f-block elements? Distinguish between lanthanoid and actinoid.

(i)with reference to structural variability and chemical reactivity write the differences between lanthanoids and actinoids (ii) Mame a member of the lanthanoid series which is well known to exhibit +4 oxidation state (iii) Complete the following equation : MnO_(4)^(-)+8H^(+)+5e^(-)rarr (iv) out of Mn^(3+) and Cr^(3+) which is ore paramagnetic and why? Atomic nos : Mn =25 Cr =24

Select the correct statements (s) for the comparision of lanthanoids with actinoids.

Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

Variation OF Atomic Size Along Group -G-1,G-2,G-14,G-15,G-16,G-17,G-18 || Exception OF Boron Family (G-13) || Transition Contraction || Variation OF Size in d block || Lanthanoid and Actinoid Contraction || ds in AR - In a Period/In a Group

(a) Account for the following : (i) Transition metals form large number of complex compounds (ii) The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic (iii) E^(@) value for the Mn^(3+)//Mn^(2+) couple is highly positive (+1.57V) as compare to Cr^(3+)//Cr^(2+) (b) Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.