A compound with delocalised electrons is more stable than that compound would be if all its electrons were localised.
The extra stability, a compound gains as a result of having delocalised electrons, is called delocalisation energy.
- If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
- If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion
- If Assertion is true but Reason is false
- If both Assertion and Reason are false
The Correct Option is B
Solution and Explanation
Top Questions on d block elements
- The d-d transitions in [Mn(H2O)6]2+ and [Ti(H2O)4]3+ , respectively, are [Ignore spin-orbit coupling and Jahn-Teller distortion.]
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[Ignore spin-orbit coupling and Jahn-Teller distortion.]- IIT JAM CY - 2024
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- For the reaction shown below
![1/2 Mn2 (CO)10+Na Na[Mn(CO)5 ] CH3Cl-NaCl [CH3Mn(CO)5](https://images.collegedunia.com/public/qa/images/content/2024_07_31/image_a08f12a11722411541392.png)
the oxidation states of Mn in P and Q, respectively, are- IIT JAM CY - 2024
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- [Co(NH3)5(SO4)]Br and [Co(NH3)5Br]SO4 are examples of
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Questions Asked in AIIMS exam
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Assertion (A) : 02 is liberated in the non-cyclic photophosphorylation.
Reason (R) : Liberation of oxygen is due to photolysis of water.
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Reason (R) : Cro-Magnon man had slightly prognathous face.
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Assertion: Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.
Reason: Orbital velocity of a satellite is greater than its escape velocity.
In the light of the above statements, choose the correct answer from the options given below- AIIMS - 2019
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Reason (R) : In bacteria, transcription and translation occurs in cytoplasm.
In the light of the above statements, choose the correct answer from the options given below
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- Transcription
Concepts Used:
d block elements
The elements, in the columns of the periodic table in which d subshells are being occupied are known as d block elements.
These are the elements that have the capability of forming stable cations with incompletely filled d orbitals. Elements like mercury and Zinc are not considered transition metals because they have electronic configurations: (n-1)d10 ns2. These elements have filled d-orbitals in their ground state and, therefore, even in some of their oxidation states.
General Properties Of d-Block Elements
- Multiple oxidation states- The oxidation states of d block elements show very few energy gaps; therefore, they exhibit many oxidation states. Also, the energy difference between s and d orbital is very less. Therefore both the electrons are involved in ionic and covalent bond formation, which ultimately leads to multiple oxidation states.
- Formation of complex compounds- Ligands show a binding behaviour and can form so many stable complexes with the help of transition metals. This property is mainly due to:
- Availability of vacant d orbitals.
- Comparatively small sizes of metals.
- Hardness- Transition elements are tough and have high densities because of the presence of unpaired electrons.
- Melting and boiling points- Melting and boiling points of transition are very high. This is because of the presence of unpaired electrons and partially filled d orbitals. Because of these two things, they form strong bonds and therefore have high melting and boiling points.
- Atomic radii- The atomic and ionic radius of the transition elements decreases as we move from Group 3 to group 6. However, it remains the same between group 7 and group 10, and from group 11 to group 12 increases.
- Ionization enthalpy- The ionization enthalpies of the transition elements are generally on the greater side as compared to the S block elements