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प्रश्न
Which transition metal of 3d series has positive E° (M2+/M) value and why?
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उत्तर
Copper is the transition metal of 3d series that exhibits positive E0(M2+/M). The value of E0(M2+/M) for copper is (+0.34). This happens because the E0(M2+/M) value of a metal depends on the energy changes involved in the following:
1. Sublimation energy: The energy required for converting one mole of an atom from the solid state to the gaseous state.
M(s)→→ M(g) ΔsH (Sublimation energy)
2. Ionisation energy: The energy required to take out electrons from one mole of atom in the isolated gaseous state.
M(g) →→ M2+(g) ΔiH (Ionisation energy)
3. Hydration energy: The energy released when one mole of ions are hydrated.
M2+(g) →→M2+(aq) ΔhydH (Hydration energy)
Since, copper has a high energy of atomisation and low hydration energy, the E0(M2+/M) value for copper is positive.
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संबंधित प्रश्न
Write down the electronic configuration of Cr3+.
Write down the electronic configuration of Pm3+.
Write down the electronic configuration of Mn2+.
Write down the electronic configuration of Th4+.
What is effective atomic number of Fe (z = 26) in [Fe(CN)6]4-?
(a) 12
(b) 30
(c) 26
(d) 36
Account for the following:
Mn2+ is more stable than Fe2+ towards oxidation to +3 state.
Explain the observation, at the end of each period, there is a slight increase in the atomic radius of d-block elements.
Name the element of 3d series which exhibits the largest number of oxidation states. Give reason.
Define transition metals.
Match the properties with the elements of 3d series:
| (i) | lowest enthalpy of atomisation | (p) | Sc |
| (ii) | shows maximum number of oxidation states | (q) | Mn |
| (iii) | transition metal that does not form coloured compounds |
(r) | Zn |
| (s) | Ti |
