Answer:
The correct answer to your question is: b. 1
Explanation:
1. Ar- This option is correct because the atomic number of Ar is 18, is one electron is added, it acquires a negative charge that is the charge shown next to the Ar symbol and will have the same electron configuration that K has (atomic number 19).
2. Rb+ If Rb loses one electron it acquires a positive charge but the atomic number of Rb is 37 very far from the atomic number of potassium (K) which atomic number is 19.
3. Si+ Silicon has an atomic number of 14 very far from the atomic number of potassium, this option is incorrect.
