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.

Question

Name the following:
(a) The most electronegative element of Period 2
(b) The largest atom of Period 3

Answer 1

Calcium Chloride (CaCl₂) Formation

1. Calcium (Ca)

Atomic number: 20
Electronic configuration: 2, 8, 8, 2
Valence electrons: 2
Calcium achieves stability by losing 2 electrons, forming 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, forming a Cl⁻ ion.

Cl + e⁻ → Cl⁻

3. CaCl₂ Formation

A calcium atom loses 2 electrons, each gained by a chlorine atom.
Therefore, 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, forming 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 each accept one, forming the ionic compound CaCl₂ through complete electron transfer and the formation of oppositely charged ions.