Question

Show the formation of calcium chloride by the transfer of electrons from one element to the other. Atomic Number of calcium and chlorine is 20 and 17 respectively.

Answer 1

Formation of Calcium Chloride (CaCl₂)

1. Calcium (Ca)

• Atomic number: 20
• Electronic configuration: 2, 8, 8, 2
• Valence electrons: 2
• To achieve stability, calcium loses 2 electrons and forms a Ca²⁺ ion

Ca → Ca²⁺ + 2e⁻

2. Chlorine (Cl)

• Atomic number: 17
• Electronic configuration: 2, 8, 7
• Valence electrons: 7
• To complete its octet, chlorine gains 1 electron to form a Cl⁻ ion

Cl + e⁻ → Cl⁻

3. Formation of CaCl₂

One calcium atom loses 2 electrons → each electron is gained by a separate chlorine atom.
Thus, one calcium atom combines with two chlorine atoms:

Ca + 2Cl → Ca²⁺ + 2Cl⁻ → CaCl₂

The Ca²⁺ and Cl⁻ ions are held together by strong electrostatic (ionic) bonds to form solid calcium chloride.

4. Optional: Electron-Dot Structure

Visual representation of electron transfer:

Ca (••) + 2 × Cl (•••••••) → Ca²⁺ [Cl (••••••••)]⁻ [Cl (••••••••)]⁻

(•• represents valence electrons; Cl gains 1 electron to complete its octet)

Conclusion:

Calcium donates two electrons, chlorine atoms accept one electron each, forming an ionic compound CaCl₂ through complete transfer of electrons and formation of oppositely charged ions.