Question

Show the formation of ionic compound CaO with electron dot structure.

Hint:

Ca loses 2e$^-$, O gains 2e$^-$ → Ionic bond forming CaO.

Answer 1

Formation of Ionic Compound CaO with Electron Dot Structure

Calcium oxide (CaO) is an ionic compound formed by the transfer of electrons from calcium (Ca) to oxygen (O).

Step 1: Electronic Configuration

Calcium (Ca), atomic number 20:
Electronic configuration = 2, 8, 8, 2
It has 2 electrons in its outermost shell.

Oxygen (O), atomic number 8:
Electronic configuration = 2, 6
It has 6 electrons in its outermost shell.

Step 2: Electron Transfer

Calcium loses 2 electrons to attain stable noble gas configuration.
Oxygen gains 2 electrons to complete its octet.

Ca → Ca²⁺ + 2e⁻
O + 2e⁻ → O²⁻

Step 3: Electron Dot Structure Representation

Before transfer:

Ca : ••
O : •• •• •• (six valence electrons)

After transfer:

Ca²⁺ [ ]²⁺
O²⁻ [ •• •• •• •• ]²⁻

Oxygen now has 8 electrons in its outermost shell (complete octet).

Final Representation:
Ca²⁺ O²⁻

The oppositely charged ions attract each other due to strong electrostatic forces, forming the ionic compound CaO.

Conclusion:
Calcium oxide (CaO) is formed by transfer of two electrons from calcium to oxygen, resulting in Ca²⁺ and O²⁻ ions held together by ionic bond.