* Metal and Nonmetal: Calcium (Ca) is a metal, and nitrogen (N) and oxygen (O) are nonmetals. Ionic compounds generally form between metals and nonmetals.

* Electrostatic Attraction: Metals tend to lose electrons to form positively charged ions (cations), while nonmetals tend to gain electrons to form negatively charged ions (anions). In Ca(NO3)2, calcium loses two electrons to become Ca²⁺, while the nitrate group (NO3) gains one electron to become NO3⁻. The opposite charges attract, forming an ionic bond.

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