Chlorine Atom (Cl)
* Atomic Number: 17, meaning it has 17 protons and 17 electrons.
* Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁵
Explanation:
* The electron configuration follows the Aufbau principle and Hund's rule, filling orbitals in order of increasing energy.
* 1s²: The first energy level (n=1) has two electrons in the 1s orbital.
* 2s²: The second energy level (n=2) has two electrons in the 2s orbital.
* 2p⁶: The second energy level also has six electrons in the three 2p orbitals.
* 3s²: The third energy level (n=3) has two electrons in the 3s orbital.
* 3p⁵: The third energy level has five electrons in the three 3p orbitals.
Chloride Ion (Cl⁻)
* Formation: Chlorine gains one electron to achieve a stable octet (eight electrons) in its outer shell.
* Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶
Explanation:
* The chloride ion now has 18 electrons (17 original + 1 gained).
* The added electron fills the last 3p orbital, giving it a full outer shell.
Key Takeaway:
* The chloride ion is more stable than the chlorine atom because it has a full outer shell of electrons.
