Properties Of D Block Elements

Generally, -block elements are called transition elements as they contain inner partially filled -subshell. Thus, their general electronic configuration is .

Concept: Chemistry (d-Block Elements) - Colour of Transition Metal Ions.

Step 1: Recall the condition for colour in transition metal ions. Transition metal ions typically exhibit colour in aqueous solutions due to d-d electronic transitions. This requires the presence of at least one unpaired electron in the d-orbitals (i.e., a partially filled d-subshell, to ). If the d-subshell is completely empty ( ) or completely full ( ), no d-d transition is possible, and the ion will be colourless.

Step 2: Determine the electronic configuration of . Titanium (Ti) has an atomic number of 22, with the ground state configuration . Losing three electrons to form results in the configuration . Since it has one unpaired electron, it undergoes d-d transitions and produces a coloured (violet) solution.

Step 3: Determine the electronic configuration of . Vanadium (V) has an atomic number of 23, with the ground state configuration . Losing three electrons to form yields . It has two unpaired electrons, so it is coloured (green/blue).

Step 4: Determine the electronic configuration of . Copper (Cu) has an atomic number of 29, with the anomalous ground state configuration . Losing two electrons to form gives . It has one unpaired electron, making its aqueous solution coloured (blue).

Step 5: Determine the electronic configuration of and conclude. Scandium (Sc) has an atomic number of 21, with the ground state configuration . To form the ion, it loses all three of its valence electrons, resulting in the stable noble gas configuration . With absolutely zero d-electrons available for transitions, it cannot absorb visible light. Therefore, its aqueous solution is entirely colourless. $ $

Tungsten (W) has the highest melting point among all d-block elements and even among all metals, with a melting point of approximately 3422°C. This is due to its strong metallic bonding and high atomic number, which results in a greater number of delocalized electrons participating in bonding, thereby strengthening the metallic bond.

Concept: The magnetic moment of transition metal ions arises mainly due to the presence of unpaired electrons. The greater the number of unpaired electrons, the larger the magnetic moment. The magnetic moment is calculated using the spin-only formula: where is the number of unpaired electrons.

Step 1: Electronic configuration of Mn. Atomic number of Mn = 25

Step 2: Electronic configuration of . Two electrons are removed from the orbital. This configuration contains 5 unpaired electrons.

Step 3: Apply the magnetic moment formula. Thus, the approximate magnetic moment of is 5.9 BM.