A neutral Chlorine atom has 17 electrons. What is the “Electron Configuration” for these electrons?
The correct answer and explanation is:
The electron configuration for a neutral chlorine atom, which has 17 electrons, is:
1s² 2s² 2p⁶ 3s² 3p⁵
Here’s how to understand this configuration:
- The electron configuration represents the distribution of electrons across different energy levels (shells) and sublevels (orbitals) in an atom. The number before each letter represents the energy level (or shell), and the superscript indicates the number of electrons in that sublevel.
- 1s²: The first energy level (shell) can hold a maximum of 2 electrons, and these electrons occupy the 1s orbital. Chlorine’s first two electrons are placed in this orbital.
- 2s² 2p⁶: The second energy level can hold a total of 8 electrons. The 2s orbital holds 2 electrons, and the 2p orbital holds 6 electrons. This accounts for the second set of 8 electrons in chlorine.
- 3s² 3p⁵: The third energy level can also hold a maximum of 8 electrons, but since chlorine only has 17 electrons in total, the 3s orbital holds 2 electrons, and the 3p orbital holds 5 electrons, leaving 3 available spots in the 3p orbital.
Chlorine’s electron configuration ends with 3p⁵, indicating that there is one electron missing from the 3p orbital to complete a full octet, which is why chlorine is reactive and tends to gain one more electron to form a stable chloride ion (Cl⁻).
The electron configuration is important because it determines how an atom interacts with other atoms. The outermost electrons (in the 3p orbital for chlorine) play a key role in chemical bonding and reactivity.