Trying to find the right answer to this..

Exactly half-filled and completely filled subshells are relatively more stable. Species try to attain the state of exactly half-filled and completely filled subshells configuration. Mn 2+ has extra stability as it has exactly half filled configuration of 4s° 3d 5 in its outermost shell while Fe 2+ has 45° 3d 6 configuration. Therefore, Fe 2+ has a tendency to loose one electron (or tends to oxidise to Fe 3+ ) to acquire extra stability by having 4s 0 3d 5 configuration. Fe 2+ → Fe 3+ + e – (4s 0 3d 6 ) (4s 0 3d 5 ) Since Mn 2+ has half filled orbital thus it is more stable to Fe 2+ .

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

The d-And-f-Block Elements

Short Answer Type

121.

What is the effect of increasing pH in K₂Cr₂O₇, solution?

124 Views

122.

Within a periodic group of transition elements the possibility of exhibiting maximum oxidation state increases with atomic number. Why?

115 Views

123. Write down the electronic configuration of:
(i) Cr³⁺ (ii) Cu⁺ (iii) Co²⁺(iv) Mn²⁺ (v) Pm³⁺(vi) Ce⁴⁺ (vii) Lu²⁺ (viii) Th⁴⁺

367 Views

124. Why are Mn²⁺ compounds more stable than Fe²⁺ towards oxidation to their +3 state?

Exactly half-filled and completely filled subshells are relatively more stable. Species try to attain the state of exactly half-filled and completely filled subshells configuration.
Mn²⁺ has extra stability as it has exactly half filled configuration of 4s° 3d⁵ in its outermost shell while Fe²⁺ has 45° 3d⁶ configuration. Therefore, Fe²⁺ has a tendency to loose one electron (or tends to oxidise to Fe³⁺) to acquire extra stability by having 4s⁰ 3d⁵configuration.
Fe²⁺→ Fe³⁺ + e^–(4s⁰3d⁶) (4s⁰3d⁵)
Since Mn²⁺ has half filled orbital thus it is more stable to Fe²⁺.

394 Views

Long Answer Type

125. Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?

683 Views

126. To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with example.

166 Views

Short Answer Type

127. What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of their atoms: 3d³, 3d⁵, 3d⁸ and 3d⁴?

295 Views

128. Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.

236 Views

Long Answer Type

129. What is lanthanoid contraction? What are the consequences of lanthanoid contraction?

697 Views

130. What are the characteristics of the transition elements and why are they called transition elements? Which of the d-block elements may not be regarded as the transition elements?

427 Views