Question Bank [2022] — Chemistry STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceChemistryQuestion Bank [2022]4 Marks
Question
Explain the trend in an Oxidation state of $3d$ elements.
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Answer
Trends in oxidation state of $3d$ elements:
1. One of the notable features of transition elements is the great variety of oxidation states they show in their compounds.
2. Loss of $4\ s$ and $3\ d$ electrons progressively leads to formation of ions. The transition elements display a variety of oxidation states in their compounds. Loss of one $4\ s$ electron leads to the formation of $M ^{+}$ion, loss of two $4\ s$ electrons gives a $M ^{2+}$ ion while loss of unpaired $3\ d$ and $4\ s$ electrons gives $M ^{3+}, M ^{4+}$ ions and so on.
3. As the number of unpaired electrons in $3d$ orbitals increases, the number of oxidation states shown by the element also increases. Scandium has only one unpaired electron. It shows two oxidation states while manganese with $5$ unpaired d electrons shows six different oxidation states.
4. The elements which give the greatest number of oxidation states occur in or near the middle of the series. Manganese, for example, shows oxidation states from $+2$ to $+7$ .
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