Which of the following characteristic is not the point of similarity between lanthanoids and actinoids?

Options

A. Both are strongly reducing in nature
B. Both have stable oxidation state of +3
C. Both have same tendency towards complex formation
D. Both are electropositive in nature

Answer

To solve the question regarding the characteristic that is not a point of similarity between lanthanoids and actinoids, we can follow these steps:

### Step 1: Understand the Groups
Lanthanoids and actinoids are two series of elements in the periodic table. Lanthanoids consist of the 15 elements from lanthanum (La) to lutetium (Lu), while actinoids consist of the 15 elements from actinium (Ac) to lawrencium (Lr).

**Hint:** Identify the elements in both series to understand their positions in the periodic table.

### Step 2: Identify Common Characteristics
Both lanthanoids and actinoids share several characteristics:
- They are both f-block elements.
- They have similar oxidation states, often exhibiting a stable oxidation state of +3.
- They tend to form complex compounds.
- They are known for their electropositive nature and strong reducing properties.

**Hint:** List the properties of both groups to see which are shared.

### Step 3: Identify Differences
While they share many similarities, there are also differences:
- The lanthanoids fill the 4f orbitals, while actinoids fill the 5f orbitals.
- The actinoids are generally more radioactive than lanthanoids.
- The actinoids show a wider range of oxidation states compared to lanthanoids.

**Hint:** Focus on the electronic configuration and radioactivity to find the differences.

### Step 4: Analyze the Options
The question asks for a characteristic that is not a point of similarity. The options typically include:
1. Oxidation states
2. Electropositivity
3. Tendency towards complex formation
4. Filling of f orbitals

From the analysis:
- Oxidation states are similar (+3).
- Electropositivity is also a shared characteristic.
- Tendency towards complex formation is similar but can vary in strength.
- The filling of f orbitals is different (4f for lanthanoids and 5f for actinoids).

**Hint:** Compare each option against the characteristics you’ve identified.

### Step 5: Conclusion
The characteristic that is not a point of similarity between lanthanoids and actinoids is the filling of the f orbitals. Therefore, the correct answer is the option that refers to this difference.

**Final Answer:** The characteristic that is not a point of similarity is the filling of f orbitals.