Which of the following shows the electronic configuration of `Ca^(2+)`?

Options

A. He
B. Ne
C. Ar
D. `F^(-)`

Explanation

To determine the electronic configuration of the calcium di-positive ion, \( Ca^{2+} \), we will follow these steps:

### Step 1: Identify the Atomic Number of Calcium
Calcium (Ca) has an atomic number of 20. This means that a neutral calcium atom has 20 electrons.

### Step 2: Write the Electronic Configuration of Neutral Calcium
The electronic configuration of a neutral calcium atom can be written based on the distribution of its 20 electrons:
- The first shell can hold up to 2 electrons.
- The second shell can hold up to 8 electrons.
- The third shell can hold up to 8 electrons.
- The fourth shell can hold up to 2 electrons.

Thus, the electronic configuration of neutral calcium is:
\[ 2, 8, 8, 2 \]

### Step 3: Determine the Configuration for \( Ca^{2+} \)
Since \( Ca^{2+} \) indicates that calcium has lost 2 electrons, we need to remove 2 electrons from the outermost shell (the fourth shell in this case).

After losing 2 electrons, the electronic configuration for \( Ca^{2+} \) becomes:
\[ 2, 8, 8 \]

### Step 4: Compare with Given Options
Now, we need to compare this configuration \( 2, 8, 8 \) with the options provided in the question.

- Helium (He) has an atomic number of 2, so its configuration is \( 2 \).
- Neon (Ne) has an atomic number of 10, so its configuration is \( 2, 8 \).
- Argon (Ar) has an atomic number of 18, so its configuration is \( 2, 8, 8 \).
- Fluorine (F) has an atomic number of 9, so its configuration is \( 2, 7 \). For the fluorine anion \( F^{-} \), it gains one electron, resulting in \( 2, 8 \).

Among these, the configuration that matches \( Ca^{2+} \) is that of Argon, which is \( 2, 8, 8 \).

### Final Answer
The electronic configuration of \( Ca^{2+} \) is \( 2, 8, 8 \), which matches with Argon.

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