Which of the following arrangements shows the correct order of decreasing paramagnetism?

Options

A. NgtAlgtOgtCa
B. NgtOgtAlgtCa
C. OgtNgtAlgtCa
D. OgtNgtCagtAl

Answer

To determine the correct order of decreasing paramagnetism based on the number of unpaired electrons in the given elements, we will follow these steps:

### Step 1: Identify the Elements
We need to analyze the following elements:
1. Nitrogen (N)
2. Oxygen (O)
3. Aluminum (Al)
4. Calcium (Ca)

### Step 2: Write the Electron Configurations
Next, we will write the electron configurations for each of these elements to find the number of unpaired electrons.

1. **Nitrogen (N)**: Atomic number = 7
- Electron configuration: \(1s^2 2s^2 2p^3\)
- Number of unpaired electrons: 3 (from 2p)

2. **Oxygen (O)**: Atomic number = 8
- Electron configuration: \(1s^2 2s^2 2p^4\)
- Number of unpaired electrons: 2 (from 2p)

3. **Aluminum (Al)**: Atomic number = 13
- Electron configuration: \(1s^2 2s^2 2p^6 3s^2 3p^1\)
- Number of unpaired electrons: 1 (from 3p)

4. **Calcium (Ca)**: Atomic number = 20
- Electron configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2\)
- Number of unpaired electrons: 0 (all electrons are paired)

### Step 3: Count the Unpaired Electrons
Now we summarize the number of unpaired electrons for each element:
- Nitrogen: 3 unpaired electrons
- Oxygen: 2 unpaired electrons
- Aluminum: 1 unpaired electron
- Calcium: 0 unpaired electrons

### Step 4: Determine the Order of Decreasing Paramagnetism
The order of decreasing paramagnetism is based on the number of unpaired electrons:
- Nitrogen (3) > Oxygen (2) > Aluminum (1) > Calcium (0)

Thus, the correct order of decreasing paramagnetism is:
**Nitrogen > Oxygen > Aluminum > Calcium**

### Final Answer
The correct arrangement showing the order of decreasing paramagnetism is:
**Nitrogen > Oxygen > Aluminum > Calcium**