Which is /are true statement?

Options

A. Ions of d-block elements are coloured due to d-d transition.
B. Ions of f-block elements are coloured due to f-f transition.
C. `[Sc(H_2O)_6]^(3+)`,`[Ti(H_2O)_6]^(4+)`, are coloured complexes.
D. `Cu^(o+)` is colourless ion.

Answer

To determine which statements are true regarding the D and F block elements, we will analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement:** Ions of D block elements are colored due to DD transitions.

**Explanation:** This statement is true. D block elements have partially filled d-orbitals, which means they have unpaired electrons. When light hits these ions, the unpaired electrons can absorb energy and undergo d-d transitions, resulting in color.

### Step 2: Analyze the second statement
**Statement:** Ions of F block elements are colored due to FF transitions.

**Explanation:** This statement is also true. Similar to D block elements, F block elements also have unpaired electrons in their f-orbitals. These unpaired electrons can transition between different energy levels when light is absorbed, leading to color in these ions.

### Step 3: Analyze the third statement
**Statement:** Cadmium (Cd) in +3 oxidation state and Titanium (Ti) in +4 oxidation state are colored complexes.

**Explanation:** This statement is false. Cadmium in the +3 oxidation state has an electronic configuration of 3d^0 4s^0, meaning it has no unpaired electrons and cannot undergo d-d transitions, making it colorless. Similarly, Titanium in the +4 oxidation state also has an electronic configuration of 3d^0 4s^0, which means it is also colorless due to the absence of unpaired electrons.

### Step 4: Analyze the fourth statement
**Statement:** Cu^+ (Copper in +1 oxidation state) is a colorless ion.

**Explanation:** This statement is true. The electronic configuration of Cu^+ (atomic number 29) is 3d^10. Since the d-orbitals are fully filled, there are no unpaired electrons present, which means that Cu^+ does not absorb visible light and appears colorless.

### Conclusion
Based on the analysis:
- The true statements are:
1. Ions of D block elements are colored due to DD transitions.
2. Ions of F block elements are colored due to FF transitions.
3. Cu^+ is a colorless ion.
- The false statement is regarding Cadmium and Titanium being colored complexes.

### Final Answer:
The true statements are the first, second, and fourth.

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