The strength of bonds by 2s -2s, 2p2p and 2p-2s overlap has the order

Options

A. `s-s gt p-p gt p-s`
B. `s-s gt p-s gt p-p`
C. `p-p gt p-s gt s-s`
D. `p-p gt s-s gt p-s`

Answer

To determine the strength of bonds formed by the overlap of 2s-2s, 2p-2p, and 2p-2s orbitals, we can analyze the extent of overlap for each type of orbital interaction. Here's a step-by-step solution:

### Step 1: Understand Orbital Overlap
Orbital overlap is crucial in determining the strength of a bond. The greater the overlap between orbitals, the stronger the bond formed. We will compare three types of overlaps: 2s-2s (ss), 2p-2p (pp), and 2p-2s (sp).

### Step 2: Analyze 2p-2p Overlap (pp)
The 2p-2p overlap involves two p orbitals. The p orbitals can overlap side-by-side or end-to-end. The side-by-side overlap (which is the most effective) allows for a significant extent of overlap, leading to a strong bond. Therefore, the pp overlap is the strongest among the three types.

### Step 3: Analyze 2p-2s Overlap (sp)
The 2p-2s overlap involves one p orbital and one s orbital. The overlap between an s orbital and a p orbital is less effective than the overlap between two p orbitals. The s orbital has a spherical shape, while the p orbital has a dumbbell shape, which results in a lower extent of overlap compared to pp overlap. Thus, the sp overlap is weaker than pp overlap.

### Step 4: Analyze 2s-2s Overlap (ss)
The 2s-2s overlap involves two s orbitals. The overlap between two s orbitals is the least effective because the spherical shape of the s orbitals does not allow for significant overlap. Therefore, the ss overlap is the weakest among the three types.

### Step 5: Establish the Order of Bond Strength
Based on the analysis:
- The strongest overlap is from 2p-2p (pp).
- The next strongest is from 2p-2s (sp).
- The weakest is from 2s-2s (ss).

Thus, the order of bond strength based on overlap is:
**pp > sp > ss**

### Final Answer
The strength of bonds by 2s-2s, 2p-2p, and 2p-2s overlap has the order: **pp > sp > ss**.

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