____________solids are formed by the three-dimensional arrangements of cations and anions bound by strong coulombic (electrostatic) forces.

Ionic

The correct answer is option 3. Ionic.

Ionic solids are formed by the three-dimensional arrangements of cations and anions held together by strong coulombic (electrostatic) forces. Ionic bonds involve the transfer of electrons from one atom to another, resulting in the formation of positively charged cations and negatively charged anions, which then attract each other due to their opposite charges and form a crystalline structure.