Question

1. give the name and symbol of the ion formed when a. a chlorine atom gains one electron. b. a potassium atom loses one electron c. a barium atom loses two electrons. d. an oxygen atom gains two electrons.

Explanation:

Step1: Analyze chlorine ion formation

When a chlorine atom gains one electron, it forms a negatively - charged ion. The name is chloride ion and the symbol is $Cl^-$.

Step2: Analyze potassium ion formation

When a potassium atom loses one electron, it forms a positively - charged ion. The name is potassium ion and the symbol is $K^+$.

Step3: Analyze barium ion formation

When a barium atom loses two electrons, it forms a positively - charged ion. The name is barium ion and the symbol is $Ba^{2+}$.

Step4: Analyze oxygen ion formation

When an oxygen atom gains two electrons, it forms a negatively - charged ion. The name is oxide ion and the symbol is $O^{2-}$.

Answer:

a. Chloride ion, $Cl^-$
b. Potassium ion, $K^+$
c. Barium ion, $Ba^{2+}$
d. Oxide ion, $O^{2-}$