1. Understand Argon's Electron Configuration
Argon (Ar) has an atomic number of 18, meaning it has 18 protons and 18 electrons. Its electron configuration is:
1s² 2s² 2p⁶ 3s² 3p⁶
2. Identify Ions with the Same Number of Electrons
To have the same electron configuration as Argon, an ion must also have 18 electrons. This can be achieved by:
* Gaining electrons: Anions (negatively charged ions) are formed by gaining electrons.
* Losing electrons: Cations (positively charged ions) are formed by losing electrons.
3. Determine the Ions
Here are the ions with the same electron configuration as Argon:
* K⁺ (Potassium ion): Potassium (K) has 19 electrons. By losing one electron, it becomes K⁺ with 18 electrons.
* Ca²⁺ (Calcium ion): Calcium (Ca) has 20 electrons. By losing two electrons, it becomes Ca²⁺ with 18 electrons.
* Cl⁻ (Chloride ion): Chlorine (Cl) has 17 electrons. By gaining one electron, it becomes Cl⁻ with 18 electrons.
* S²⁻ (Sulfide ion): Sulfur (S) has 16 electrons. By gaining two electrons, it becomes S²⁻ with 18 electrons.
In summary: The ions K⁺, Ca²⁺, Cl⁻, and S²⁻ all have the same electron configuration as Argon. This is because they all have 18 electrons, just like Argon.
