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The d & f Block Elements — Chemistry STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceChemistryThe d & f Block Elements5 Marks
Question
  1. Give three points of difference between lanthanoids and actinoids.
  2. Give reason and select one atom$/$ion which will exhibit asked property:
  1. $Sc^{3+}$ or $Cr^{3+} ($Exhibit diamagnetic behaviour$).$
  2. $Cr$ or $Cu ($High melting and boiling point$).$
✓

Answer

  1.  
S. No.
Lanthanoids
Actinoids
$1.$
Most of them are not radioactive.
All are radioactive.
$2.$
Don’t show a wide range of oxidation state.
Show a wide range of oxidation states.
$3.$
Most of their ions are colourless.
Most of their ions are coloured.
  1.  
  1. $Sc^{+3},$ because of absence of unpaired electron.
  2. $Cr,$ because of presence of strong intermetallic bonding than $Cu.$

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