Which of these element pairs possess nearly the same atomic radius?

Options

A. Fe, Co
B. Te, I
C. N, O
D. All of these

Answer

To determine which pairs of elements possess nearly the same atomic radius, we can analyze the atomic numbers and electronic configurations of the given elements. Here’s a step-by-step solution:

### Step 1: Identify the Element Pairs
We need to identify the pairs of elements given in the question. For this example, let's consider the pairs: Iron (Fe) and Cobalt (Co), Tellurium (Te) and Iodine (I), and Nitrogen (N) and Oxygen (O).

### Step 2: Write the Electronic Configurations
- **Iron (Fe)**: Atomic number 26 → Electronic configuration: [Ar] 3d^6 4s^2
- **Cobalt (Co)**: Atomic number 27 → Electronic configuration: [Ar] 3d^7 4s^2
- **Tellurium (Te)**: Atomic number 52 → Electronic configuration: [Kr] 4d^10 5s^2 5p^4
- **Iodine (I)**: Atomic number 53 → Electronic configuration: [Kr] 4d^10 5s^2 5p^5
- **Nitrogen (N)**: Atomic number 7 → Electronic configuration: 1s^2 2s^2 2p^3
- **Oxygen (O)**: Atomic number 8 → Electronic configuration: 1s^2 2s^2 2p^4

### Step 3: Analyze the Atomic Radius
1. **Iron and Cobalt**:
- Both have the same outer electron configuration in the 4s subshell, and the increase in nuclear charge from Fe to Co is balanced by the additional electron in the d subshell. Thus, their atomic radii are similar.

2. **Tellurium and Iodine**:
- Both have the same outer shell (5th shell) and the addition of one electron in the 5p subshell does not significantly change the atomic radius due to the balance of nuclear charge and electron-electron repulsion.

3. **Nitrogen and Oxygen**:
- Both have the same principal quantum number (2) and the addition of one electron in the 2p subshell results in a similar atomic radius for both elements.

### Step 4: Conclusion
Based on the analysis, all three pairs (Fe & Co, Te & I, N & O) exhibit nearly the same atomic radius due to their electronic configurations and the balance of nuclear charge with electron repulsion. However, if we must select one pair that is most commonly recognized for having nearly the same atomic radius, we can conclude:

**Answer**: The pairs that possess nearly the same atomic radius are Iron (Fe) and Cobalt (Co).