The electronic configuration of the element with Atomic number 19 is

Options

A. 2,8,7
B. 2,9,8
C. 2,8,8,1
D. 2,10,7

Answer

To determine the electronic configuration of the element with atomic number 19, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number**: The atomic number (Z) of the element is 19. This indicates that there are 19 electrons in a neutral atom of this element.

2. **Understand Electron Shells**: Electrons are arranged in shells around the nucleus. The maximum number of electrons that can be accommodated in each shell is given by the formula \(2n^2\), where \(n\) is the shell level:
- 1st shell (n=1): Maximum 2 electrons
- 2nd shell (n=2): Maximum 8 electrons
- 3rd shell (n=3): Maximum 18 electrons (but for the first 19 electrons, we will only fill up to 8)
- 4th shell (n=4): Maximum 32 electrons (not relevant for this case)

3. **Fill the Electron Shells**:
- Start filling from the 1st shell: Fill 2 electrons.
- Move to the 2nd shell: Fill 8 electrons. Now we have used \(2 + 8 = 10\) electrons.
- Move to the 3rd shell: We have \(19 - 10 = 9\) electrons left to place. Fill 9 electrons in the 3rd shell.

4. **Write the Electronic Configuration**:
- The configuration can be written as:
- 1st shell: 2 electrons → 1s²
- 2nd shell: 8 electrons → 2s² 2p⁶
- 3rd shell: 9 electrons → 3s² 3p⁶ 3d¹ (but we only fill 3s and 3p for 9 electrons, so it will be 3s² 3p³)
- Therefore, the complete electronic configuration is:
- 1s² 2s² 2p⁶ 3s² 3p³

5. **Final Answer**: The electronic configuration of the element with atomic number 19 is:
- **1s² 2s² 2p⁶ 3s² 3p³**