* Electronegativity: Electronegativity is the tendency of an atom to attract electrons towards itself in a chemical bond. Oxygen is highly electronegative, while calcium is much less electronegative. This difference in electronegativity is crucial for ionic bonding.
* Electron Transfer: When calcium and oxygen react, the highly electronegative oxygen atom completely "steals" an electron from the calcium atom. This results in:
* Calcium (Ca) losing two electrons, becoming a positively charged ion (Ca²⁺).
* Oxygen (O) gaining two electrons, becoming a negatively charged ion (O²⁻).
* Electrostatic Attraction: The oppositely charged ions (Ca²⁺ and O²⁻) are then attracted to each other by strong electrostatic forces, forming the ionic compound calcium oxide.
Key Features of Ionic Bonds:
* Transfer of electrons: One atom completely loses electrons, and the other atom gains those electrons.
* Formation of ions: The electron transfer leads to the formation of oppositely charged ions.
* Electrostatic attraction: The oppositely charged ions are held together by strong electrostatic forces, forming the ionic bond.
In summary, the large difference in electronegativity between calcium and oxygen drives the transfer of electrons, leading to the formation of ions and the strong electrostatic attraction that characterizes the ionic bond in calcium oxide.
