The basic nature of the Lanthanide hydroxides decreases from `Ce(OH)_(3)`, to `Lu(OH)_(3)`This is due to

Options

A. Decrease in ionic radius
B. Due to lanthanoid contraction
C. Increase in metallic character
D. All of these

Answer

To solve the question regarding the basic nature of the lanthanide hydroxides decreasing from `Ce(OH)_(3)` to `Lu(OH)_(3)`, we can break it down into several steps:

### Step 1: Understand the Lanthanide Series
The lanthanide series consists of 15 elements from cerium (Ce) to lutetium (Lu). These elements exhibit similar properties, but there are trends in their physical and chemical characteristics.

**Hint:** Familiarize yourself with the lanthanide series and its elements.

### Step 2: Define Basic Nature of Hydroxides
The basic nature of a hydroxide refers to its ability to donate hydroxide ions (OH⁻) in solution. Stronger bases will dissociate more completely in water, releasing more OH⁻ ions.

**Hint:** Recall how basicity is measured in terms of hydroxide ion release.

### Step 3: Identify the Trend in Basicity
As we move from `Ce(OH)_(3)` to `Lu(OH)_(3)`, we observe a decrease in basicity. This means that `Ce(OH)_(3)` is a stronger base compared to `Lu(OH)_(3)`.

**Hint:** Look for trends in the periodic table, particularly in the lanthanide series.

### Step 4: Consider the Concept of Lanthanide Contraction
Lanthanide contraction refers to the gradual decrease in ionic radii of the lanthanide ions as we move from cerium to lutetium. This occurs due to the poor shielding effect of the f-electrons, leading to a stronger effective nuclear charge.

**Hint:** Understand how ionic size affects chemical properties.

### Step 5: Relate Ionic Size to Basicity
As the ionic radius decreases from `Ce³⁺` to `Lu³⁺`, the ability of these ions to stabilize hydroxide ions changes. A smaller ionic radius generally leads to a higher covalent character in the hydroxides, which reduces their basicity.

**Hint:** Think about how ionic vs. covalent character influences basicity.

### Step 6: Conclude the Reason for Decreased Basicity
The decrease in basicity from `Ce(OH)_(3)` to `Lu(OH)_(3)` can be attributed to the increase in covalent character of the hydroxides due to the lanthanide contraction. As the covalent character increases, the basic strength decreases.

**Hint:** Summarize how covalent character impacts the basicity of hydroxides.

### Final Answer
The basic nature of the lanthanide hydroxides decreases from `Ce(OH)_(3)` to `Lu(OH)_(3)` due to the lanthanide contraction, which results in a decrease in ionic radius and an increase in covalent character of the hydroxides, leading to a decrease in basic strength.