To determine the correct electron configuration for sodium (Na), we need to understand how electrons are arranged in the atomic orbitals based on the atomic number of Sodium, which is 11. This means that a sodium atom has 11 electrons to be placed in orbitals.
Here are the steps to find the correct electron configuration of sodium:
1. Identify the Number of Electrons:
Sodium has an atomic number of 11, so it has 11 electrons.
2. Follow the Aufbau Principle:
The Aufbau principle states that electrons fill orbitals starting from the lowest energy level to the highest. The order in which electron orbitals are filled is:
1s
2s
2p
3s
3p
4s
* 3d
3. Distribute the Electrons in Orbitals:
- The 1s orbital can hold 2 electrons: [tex]\(1s^2\)[/tex], so we place 2 electrons there.
- The 2s orbital can hold 2 electrons: [tex]\(2s^2\)[/tex], so we place the next 2 electrons there.
- The 2p orbital can hold 6 electrons: [tex]\(2p^6\)[/tex], so we place the next 6 electrons there.
- The 3s orbital can hold 2 electrons, but since we have only 1 more electron left, we place that single electron in the 3s orbital: [tex]\(3s^1\)[/tex].
Summarizing this, the electron configuration for sodium should be:
[tex]\[ 1s^2 2s^2 2p^6 3s^1 \][/tex]
4. Compare with Given Options:
- Option 1: [tex]\(1s^2 2s^2 2p^6 2d^1\)[/tex] - This configuration is incorrect because after the 2p orbital, electrons fill the 3s orbital, not the 2d orbital.
- Option 2: [tex]\(1s^2 2s^2 2p^6 3s^1\)[/tex] - This configuration correctly places all 11 electrons.
- Option 3: [tex]\(1s^2 2p^6 3d^3\)[/tex] - This configuration is incorrect because it skips the 2s and 3s orbitals, and 3d comes after 3p, not directly after 2p.
Thus, the correct electron configuration for sodium (Na) is:
[tex]\[ 1s^2 2s^2 2p^6 3s^1 \][/tex]
So, the correct answer is option 2.
