Question: How are the electron configurations of elements beyond argon determined? 1. Arrange: Create the correct electron configuration for argon. Then, click Next element to get to potassium (K). Click once in the first 3d orbital, and then click Check What feedback is given? 2 Rearrange: The 4s subshell is a lower energy subshell than 3d, so it is filled first. Remove the electron from the 3d orbital and place it in the 4s orbital. Click Check. (Note: For simplicity, all but the outer shell electrons will disappear on the Bohr Model) Is this configuration correct? What is the configuration?
The Correct Answer and Explanation is :
The electron configuration of elements beyond argon (element number 18) is determined by following the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to the highest. This can be visualized in an electron configuration diagram, which indicates the order in which orbitals are filled.
- Argon’s Electron Configuration:
Argon (Ar) has an atomic number of 18, meaning it has 18 electrons. The electron configuration of argon is:
[
1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6
]
This configuration shows that all the lower orbitals are fully occupied, leaving the 3p orbital as the outermost shell for argon. - Electron Configuration for Potassium (K):
Potassium (K) has an atomic number of 19, so it has 19 electrons. After argon’s configuration, potassium will have one more electron, which will go into the next available orbital, the 4s orbital. The electron configuration for potassium is:
[
1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^1
]
This shows that the 4s orbital is filled with one electron, making potassium the first element to have an electron in the 4s orbital. - Energy Subshells:
The 4s orbital is lower in energy than the 3d orbital, so despite the fact that the 3d orbital is higher in the periodic table, it gets filled after the 4s orbital. This is why, when determining the electron configuration for potassium, the 4s orbital is filled first, not the 3d. - Rearrange:
If an electron is moved incorrectly into the 3d orbital (as mentioned in your question), the configuration would be wrong. The correct configuration places the electron in the 4s orbital first. The energy levels of the orbitals dictate this behavior. Removing the electron from the 3d orbital and placing it into the 4s orbital corrects this issue.
Thus, the correct configuration for potassium (K) is:
[
1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^1
]
This arrangement respects the energy levels of the orbitals and follows the Aufbau principle.