What is the atomic number of the element with the maximum number of unpaired 4p electron.

Options

A. 33
B. 26
C. 23
D. 15

Answer

To determine the atomic number of the element with the maximum number of unpaired 4p electrons, we can follow these steps:

### Step 1: Understand the Electron Configuration
The 4p subshell can hold a maximum of 6 electrons (2 in each of the 3 orbitals). To have the maximum number of unpaired electrons in the 4p subshell, we need to fill it with 3 electrons, as each of the 3 orbitals can hold one electron.

### Step 2: Fill the Electron Configuration
We need to write the electron configuration leading up to the 4p subshell. The order of filling the subshells according to the Aufbau principle is as follows:

1. 1s²
2. 2s²
3. 2p⁶
4. 3s²
5. 3p⁶
6. 4s²
7. 3d¹⁰
8. 4p³ (for maximum unpaired electrons)

### Step 3: Calculate the Atomic Number
Now, we need to calculate the atomic number by adding the number of electrons in each subshell:

- 1s² = 2 electrons
- 2s² = 2 electrons
- 2p⁶ = 6 electrons
- 3s² = 2 electrons
- 3p⁶ = 6 electrons
- 4s² = 2 electrons
- 3d¹⁰ = 10 electrons
- 4p³ = 3 electrons

Adding these together:
\[ 2 + 2 + 6 + 2 + 6 + 2 + 10 + 3 = 33 \]

### Step 4: Identify the Element
The atomic number 33 corresponds to the element Arsenic (As).

### Final Answer
The atomic number of the element with the maximum number of unpaired 4p electrons is **33**.

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