Atomic radius of Fe is closest to

Options

A. `Co`
B. `K`
C. `Ag`
D. `Sc `

Explanation

To determine the atomic radius of iron (Fe) and find which of the given elements (Co, K, Ag, and Sc) it is closest to, we can follow these steps:

### Step 1: Identify the Electronic Configuration of Iron (Fe)
- Iron has an atomic number of 26.
- Its electronic configuration can be written as:
\[ \text{Fe: } [\text{Ar}] 3d^6 4s^2 \]

### Step 2: Understand the Position of Iron in the Periodic Table
- Iron (Fe) is located in the 3d transition series of the periodic table.
- The elements in this series (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) have similar properties and atomic radii.

### Step 3: Compare Atomic Radii of the Given Elements
- The elements provided for comparison are:
- Co (Cobalt)
- K (Potassium)
- Ag (Silver)
- Sc (Scandium)

### Step 4: Analyze the Atomic Radii Trends
- Generally, atomic radius decreases across a period due to increased nuclear charge, which pulls electrons closer to the nucleus.
- In the d-block, the atomic radius tends to be relatively constant due to the filling of d-orbitals, which provides a shielding effect.

### Step 5: Look Up Atomic Radii Values
- Approximate atomic radii values (in pm) for the elements are:
- Fe: ~140 pm
- Co: ~125 pm
- K: ~227 pm
- Ag: ~165 pm
- Sc: ~144 pm

### Step 6: Determine the Closest Value
- From the values, we can see that:
- Co (125 pm) is the closest to Fe (140 pm).

### Conclusion
- Therefore, the atomic radius of Fe is closest to that of Cobalt (Co).

### Final Answer
- The atomic radius of Fe is closest to Co.

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