Question

use criss-cross method to write the formula for each of the following.

1. potassium nitride
2. calcium iodide
3. strontium phosphide
4. aluminum selenide

name these compounds:

1. $mg_3n_2$
2. $srf_2$
3. $li_3p$
4. $cs_3n$
5. $rb_2o$
6. $bai_2$
7. $aln$
8. $mgo$
9. $znbr_2$
10. $al_2o_3$
11. $cao$
12. $li_2o$

write the formulas for these compounds:

1. calcium iodide
2. sodium carbide
3. strontium phosphide
4. lithium phosphide

Explanation:

Step1: Identify ion charges (Q5)

Potassium: $\text{K}^+$, Nitride: $\text{N}^{3-}$

Step2: Criss-cross charges (Q5)

Swap charges as subscripts: $\text{K}_3\text{N}$

Step3: Identify ion charges (Q6)

Calcium: $\text{Ca}^{2+}$, Iodide: $\text{I}^-$

Step4: Criss-cross charges (Q6)

Swap charges as subscripts: $\text{CaI}_2$

Step5: Identify ion charges (Q7)

Strontium: $\text{Sr}^{2+}$, Phosphide: $\text{P}^{3-}$

Step6: Criss-cross charges (Q7)

Swap charges as subscripts: $\text{Sr}_3\text{P}_2$

Step7: Identify ion charges (Q8)

Aluminum: $\text{Al}^{3+}$, Selenide: $\text{Se}^{2-}$

Step8: Criss-cross charges (Q8)

Swap charges as subscripts: $\text{Al}_2\text{Se}_3$

Step9: Name ionic compound (Q9)

Cation: Magnesium, Anion: Nitride → Magnesium nitride

Step10: Name ionic compound (Q10)

Cation: Strontium, Anion: Fluoride → Strontium fluoride

Step11: Name ionic compound (Q11)

Cation: Lithium, Anion: Phosphide → Lithium phosphide

Step12: Name ionic compound (Q12)

Cation: Cesium, Anion: Nitride → Cesium nitride

Step13: Name ionic compound (Q13)

Cation: Rubidium, Anion: Oxide → Rubidium oxide

Step14: Name ionic compound (Q14)

Cation: Barium, Anion: Iodide → Barium iodide

Step15: Name ionic compound (Q15)

Cation: Aluminum, Anion: Nitride → Aluminum nitride

Step16: Name ionic compound (Q16)

Cation: Magnesium, Anion: Oxide → Magnesium oxide

Step17: Name ionic compound (Q17)

Cation: Zinc, Anion: Bromide → Zinc bromide

Step18: Name ionic compound (Q18)

Cation: Aluminum, Anion: Oxide → Aluminum oxide

Step19: Name ionic compound (Q19)

Cation: Calcium, Anion: Oxide → Calcium oxide

Step20: Name ionic compound (Q20)

Cation: Lithium, Anion: Oxide → Lithium oxide

Step21: Write formula (Q21)

Calcium $\text{Ca}^{2+}$, Iodide $\text{I}^-$ → $\text{CaI}_2$

Step22: Write formula (Q22)

Sodium $\text{Na}^+$, Carbide $\text{C}^{4-}$ → $\text{Na}_4\text{C}$

Step23: Write formula (Q23)

Strontium $\text{Sr}^{2+}$, Phosphide $\text{P}^{3-}$ → $\text{Sr}_3\text{P}_2$

Step24: Write formula (Q24)

Lithium $\text{Li}^+$, Phosphide $\text{P}^{3-}$ → $\text{Li}_3\text{P}$

Answer:

1. $\text{K}_3\text{N}$
2. $\text{CaI}_2$
3. $\text{Sr}_3\text{P}_2$
4. $\text{Al}_2\text{Se}_3$
5. Magnesium nitride
6. Strontium fluoride
7. Lithium phosphide
8. Cesium nitride
9. Rubidium oxide
10. Barium iodide
11. Aluminum nitride
12. Magnesium oxide
13. Zinc bromide
14. Aluminum oxide
15. Calcium oxide
16. Lithium oxide
17. $\text{CaI}_2$
18. $\text{Na}_4\text{C}$
19. $\text{Sr}_3\text{P}_2$
20. $\text{Li}_3\text{P}$