Among the elements from atomic number 1 to 36 the number of elements which have an unpaired electron in the s- subshell is

Options

A. 4
B. 7
C. 6
D. 9

Explanation

To determine the number of elements from atomic number 1 to 36 that have an unpaired electron in the s-subshell, we will follow these steps:

### Step 1: Identify the Elements and Their Electronic Configurations
We will list the elements from atomic number 1 to 36 along with their electronic configurations, focusing on the s-subshell.

- **Hydrogen (H)**: 1s¹
- **Helium (He)**: 1s²
- **Lithium (Li)**: 2s¹
- **Beryllium (Be)**: 2s²
- **Boron (B)**: 2s² 2p¹
- **Carbon (C)**: 2s² 2p²
- **Nitrogen (N)**: 2s² 2p³
- **Oxygen (O)**: 2s² 2p⁴
- **Fluorine (F)**: 2s² 2p⁵
- **Neon (Ne)**: 2s² 2p⁶
- **Sodium (Na)**: 3s¹
- **Magnesium (Mg)**: 3s²
- **Aluminum (Al)**: 3s² 3p¹
- **Silicon (Si)**: 3s² 3p²
- **Phosphorus (P)**: 3s² 3p³
- **Sulfur (S)**: 3s² 3p⁴
- **Chlorine (Cl)**: 3s² 3p⁵
- **Argon (Ar)**: 3s² 3p⁶
- **Potassium (K)**: 4s¹
- **Calcium (Ca)**: 4s²
- **Scandium (Sc)**: 4s² 3d¹
- **Titanium (Ti)**: 4s² 3d²
- **Vanadium (V)**: 4s² 3d³
- **Chromium (Cr)**: 4s¹ 3d⁵
- **Manganese (Mn)**: 4s² 3d⁵
- **Iron (Fe)**: 4s² 3d⁶
- **Cobalt (Co)**: 4s² 3d⁷
- **Nickel (Ni)**: 4s² 3d⁸
- **Copper (Cu)**: 4s¹ 3d¹⁰
- **Zinc (Zn)**: 4s² 3d¹⁰
- **Gallium (Ga)**: 4s² 4p¹
- **Germanium (Ge)**: 4s² 4p²
- **Arsenic (As)**: 4s² 4p³
- **Selenium (Se)**: 4s² 4p⁴
- **Bromine (Br)**: 4s² 4p⁵
- **Krypton (Kr)**: 4s² 4p⁶

### Step 2: Identify Unpaired Electrons in the s-subshell
Now we will check which of these elements have unpaired electrons in their s-subshell:

- **H**: 1s¹ (1 unpaired)
- **He**: 1s² (0 unpaired)
- **Li**: 2s¹ (1 unpaired)
- **Be**: 2s² (0 unpaired)
- **Na**: 3s¹ (1 unpaired)
- **Mg**: 3s² (0 unpaired)
- **K**: 4s¹ (1 unpaired)
- **Ca**: 4s² (0 unpaired)
- **Cr**: 4s¹ (1 unpaired)
- **Cu**: 4s¹ (1 unpaired)

### Step 3: Count the Elements with Unpaired Electrons
Now we will count the elements that have unpaired electrons in the s-subshell:

1. Hydrogen (H)
2. Lithium (Li)
3. Sodium (Na)
4. Potassium (K)
5. Chromium (Cr)
6. Copper (Cu)

### Conclusion
The total number of elements from atomic number 1 to 36 that have an unpaired electron in the s-subshell is **6**.

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