Which of the following electronic structure represents a metallic element ?

Options

A. 2,8,7
B. 2,8,8
C. 2,8,4
D. 2,8,1

Answer

To determine which electronic structure represents a metallic element, we need to analyze the given options based on the characteristics of metallic elements. Here’s a step-by-step solution:

### Step 1: Understand the Characteristics of Metallic Elements
Metallic elements typically have fewer electrons in their valence shell. This allows them to easily lose electrons and achieve a stable electron configuration, often resembling that of noble gases.

### Step 2: Analyze Each Option
We need to look at the electronic configurations provided in the options and count the number of electrons in the valence shell for each:

1. **Option 1:** Valence shell has 7 electrons.
- This configuration suggests that the element is likely a non-metal, as non-metals tend to gain electrons to achieve stability.

2. **Option 2:** Valence shell has a noble gas configuration (8 electrons).
- Noble gases are inert and do not typically form metallic bonds, so this option does not represent a metallic element.

3. **Option 3:** Valence shell has 4 electrons.
- Elements with 4 valence electrons can be metalloids or non-metals, and they do not easily lose electrons to form metallic bonds.

4. **Option 4:** Valence shell has 1 electron.
- This configuration is characteristic of alkali metals (like lithium, sodium, etc.), which are metallic elements. They readily lose this one electron to achieve a stable configuration.

### Step 3: Conclusion
Based on the analysis, the electronic structure that represents a metallic element is the one with **1 electron in the valence shell** (Option 4).

### Final Answer
The electronic structure that represents a metallic element is the one with **1 electron in the valence shell**.

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