Which electronic configuration corresponds to an alkali metal? 2, 2 2, 8,2 2, 8,1 2,8,8

Options

A. 2, 2
B. 2, 8,2
C. 2, 8,1
D. `2, 8, 8`

Explanation

To determine which electronic configuration corresponds to an alkali metal, we need to understand the characteristics of alkali metals. Alkali metals belong to Group 1 (or 1A) of the periodic table, and they are characterized by having one electron in their outermost shell.

### Step-by-Step Solution:

1. **Identify the Group of Alkali Metals**:
- Alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
- They all have one electron in their outermost shell.

2. **Analyze the Given Options**:
- **Option 1: 2, 2**
- This configuration suggests 2 electrons in the first shell and 2 in the second shell (total of 4 electrons). This does not correspond to an alkali metal.
- **Option 2: 2, 8, 2**
- This configuration suggests 2 electrons in the first shell, 8 in the second shell, and 2 in the third shell (total of 12 electrons). This does not correspond to an alkali metal.
- **Option 3: 2, 8, 1**
- This configuration suggests 2 electrons in the first shell, 8 in the second shell, and 1 in the third shell (total of 11 electrons). This corresponds to sodium (Na), which is an alkali metal.
- **Option 4: 2, 8, 8**
- This configuration suggests 2 electrons in the first shell, 8 in the second shell, and 8 in the third shell (total of 18 electrons). This does not correspond to an alkali metal.

3. **Conclusion**:
- The only configuration that corresponds to an alkali metal is **Option 3: 2, 8, 1**.

### Final Answer:
The electronic configuration that corresponds to an alkali metal is **2, 8, 1**.