Here's why:
* Calcium (Ca) is a metal, and it tends to lose two electrons to achieve a stable electron configuration.
* Sulfur (S) is a nonmetal, and it tends to gain two electrons to achieve a stable electron configuration.
When calcium loses its two electrons, it becomes a positively charged ion (Ca²⁺). When sulfur gains two electrons, it becomes a negatively charged ion (S²⁻). These oppositely charged ions attract each other strongly, forming an ionic bond.
Key characteristics of ionic bonds:
* Formed between metals and nonmetals.
* Involve the transfer of electrons.
* Result in the formation of positively and negatively charged ions.
* Strong electrostatic attraction between the ions.
* Usually form crystalline solids at room temperature.
