Boron shows single oxidation state due to absence of

Options

A. inert pair effect
B. Screening effect
C. Isotope effect q
D. None of these

Explanation

To solve the question "Boron shows single oxidation state due to absence of...", we need to understand the concept of oxidation states and the role of the inert pair effect in elements.

### Step-by-Step Solution:

**Step 1: Understanding Oxidation States**
- Oxidation states refer to the degree of oxidation of an atom in a compound. Elements can exhibit multiple oxidation states depending on their electronic configuration and the nature of their bonding.

**Hint 1:** Recall that oxidation states can vary based on the element's ability to lose or gain electrons.

**Step 2: Analyzing Boron's Electronic Configuration**
- Boron (B) has an atomic number of 5, and its electronic configuration is 1s² 2s² 2p¹. This means it has three valence electrons (2s² 2p¹) that can participate in bonding.

**Hint 2:** Remember that the valence electrons are the ones involved in chemical bonding and oxidation states.

**Step 3: The Concept of Inert Pair Effect**
- The inert pair effect refers to the tendency of the outermost s-electrons (in this case, the 2s electrons) to remain non-bonding or inert, especially in heavier p-block elements. This effect is more pronounced in heavier elements of groups 13 to 16.

**Hint 3:** Consider how the inert pair effect influences the bonding behavior of heavier elements compared to lighter ones.

**Step 4: Absence of Inert Pair Effect in Boron**
- In the case of boron, the inert pair effect is absent because it is a lighter element. Therefore, all three valence electrons (two from 2s and one from 2p) can participate in bonding, leading to a single oxidation state of +3.

**Hint 4:** Think about how the absence of the inert pair effect allows for more flexibility in bonding for lighter elements like boron.

**Step 5: Conclusion**
- Thus, boron shows a single oxidation state (+3) due to the absence of the inert pair effect, which allows all its valence electrons to participate in bonding.

### Final Answer:
Boron shows a single oxidation state due to the absence of the inert pair effect.