The outermost shell electronic configuration `3d^(5), 4s^(2)` represents

Options

A. `Ca`
B. `Mn`
C. Te
D. `Zn`

Answer

To determine which element corresponds to the outermost shell electronic configuration of `3d^(5), 4s^(2)`, we can follow these steps:

### Step 1: Identify the Atomic Number
The given electronic configuration `3d^(5), 4s^(2)` indicates that there are 5 electrons in the 3d subshell and 2 electrons in the 4s subshell. The total number of electrons can be calculated as follows:
- Electrons in 3d: 5
- Electrons in 4s: 2
- Total = 5 + 2 = 7

However, we need to find the atomic number corresponding to this configuration. The 3d subshell starts filling after the 4s subshell, so we need to consider the atomic number of the element.

### Step 2: Determine the Atomic Number
The atomic number can be calculated by adding the number of electrons in the filled shells before the 3d and 4s subshells:
- The 1s subshell has 2 electrons (1s²)
- The 2s and 2p subshells have 8 electrons (2s² 2p⁶)
- The 3s and 3p subshells have 8 electrons (3s² 3p⁶)
- The 4s subshell has 2 electrons (4s²)
- The 3d subshell has 5 electrons (3d⁵)

Adding these gives:
- 2 (1s) + 8 (2s, 2p) + 8 (3s, 3p) + 2 (4s) + 5 (3d) = 25

Thus, the atomic number is 25.

### Step 3: Identify the Element
Now we need to identify which element has the atomic number 25. Referring to the periodic table, the element with atomic number 25 is Manganese (Mn).

### Conclusion
The outermost shell electronic configuration `3d^(5), 4s^(2)` represents Manganese (Mn).

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