Answer:
- Ionic bond
 - Ionic bond
 - Ionic bond 
 
Step-by-step explanation:
1) Calcium = ? 
→ Ca will constitute to form ionic bond. 
2) Rubidium iodide = ? 
→ Rubidium iodide will form ionic bond. 
3) Nickel (IV) selenide = ?
→ Nickel (IV) selenide forms ionic bond.