Transition and Inner Transition Elements — Chemistry STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceChemistryTransition and Inner Transition Elements2 Marks
Question
Explain giving examples, the colour of nf electrons is about the same as those having (14-n) electrons.
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Answer
(1) Consider $Pr ^{3+}$ and $Tm ^{3+}$ ions. $Tm ^{3+}\left(4 f ^{12}\right)$ has nf electron 12 electrons. $\operatorname{Pr}^{2+}\left(4 f ^2\right)$ has $(14- n )=(14-2)=12$ electrons. Both, $Tm ^{3+}$ and $Pr ^{3+}$ are green. (2) Consider $Nd ^{3+}$ and $Er ^{3+}$ ions. $Er ^{3+}\left(4 f ^{11}\right)$ has nf electrons 11. $Nd ^{3+}\left(4 f^3\right)$ has $(14-n)$ is $(14-3)=11$ electrons. These both ions $Er ^{3+}, Na ^{3+}$ are pink in colour.
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