Directions: In the following questions, A statement of Assertion (A) ...
Transition metals have high melting points because of the involvement of greater number of (n – 1)d and ns electrons in the interatomic metallic bonding.
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Directions: In the following questions, A statement of Assertion (A) ...
Assertion (A): Transition metals have high melting point.
Reason (R): Transition metals have completely filled d-orbitals.
The correct answer to this question is option 'C', which states that Assertion (A) is true but Reason (R) is false.
Explanation:
Transition metals have high melting point:
- Transition metals are located in the d-block of the periodic table, which includes elements from group 3 to group 12.
- These metals have high melting points compared to other elements in the periodic table.
- The high melting point of transition metals can be attributed to several factors:
- Strong metallic bonding: Transition metals have strong metallic bonds due to the presence of partially filled d-orbitals, which allow for effective overlap of atomic orbitals and the formation of a delocalized sea of electrons.
- Multiple valence electrons: Transition metals have multiple valence electrons, which contribute to the formation of strong metallic bonds.
- Compact atomic structure: Transition metals have relatively compact atomic structures, which result in stronger interatomic forces and higher melting points.
Transition metals do not have completely filled d-orbitals:
- The reason provided in the statement (R) is incorrect. Transition metals do not have completely filled d-orbitals.
- In fact, one of the defining characteristics of transition metals is their ability to form compounds in which the d-orbitals are partially filled.
- The partially filled d-orbitals allow transition metals to exhibit a wide range of oxidation states and form complex compounds.
- The number of electrons in the d-orbitals can vary depending on the specific transition metal and its oxidation state.
- For example, iron (Fe) in its most common oxidation state of +2 has 6 electrons in its d-orbitals, while iron in its +3 oxidation state has 5 electrons in its d-orbitals.
In conclusion, while Assertion (A) is true and transition metals do have high melting points, Reason (R) is false as transition metals do not have completely filled d-orbitals. Therefore, the correct answer is option 'C'.