Question

writing chemical formulae (i)

1. magnesium oxide
2. lithium bromide
3. calcium nitride
4. aluminum sulfide
5. potassium iodide
6. strontium chloride
7. sodium sulfide
8. radium bromide
9. magnesium sulfide
10. aluminum nitride
11. cesium sulfide
12. potassium chloride
13. strontium phosphide
14. barium iodide
15. sodium fluoride
16. calcium bromide
17. beryllium oxide
18. strontium sulfide
19. boron fluoride
20. aluminum phosphide
21. rubidium oxide
22. calcium iodide
23. cesium oxide
24. magnesium iodide
25. lithium chloride

Explanation:

Step1: Use ion charge balancing

For each compound, match cation/anion charges to make the compound neutral. Subscripts balance total positive/negative charge.

Step2: Write correct formula

Use element symbols and subscripts (omit subscript 1) for neutral compounds.

1. Magnesium ($\text{Mg}^{2+}$) + Oxide ($\text{O}^{2-}$): charges balance 1:1

$\text{MgO}$

1. Lithium ($\text{Li}^+$) + Bromide ($\text{Br}^-$): charges balance 1:1

$\text{LiBr}$

1. Calcium ($\text{Ca}^{2+}$) + Nitride ($\text{N}^{3-}$): 3(+2) + 2(-3) = 0

$\text{Ca}_3\text{N}_2$

1. Aluminum ($\text{Al}^{3+}$) + Sulfide ($\text{S}^{2-}$): 2(+3) + 3(-2) = 0

$\text{Al}_2\text{S}_3$

1. Potassium ($\text{K}^+$) + Iodide ($\text{I}^-$): charges balance 1:1

$\text{KI}$

1. Strontium ($\text{Sr}^{2+}$) + Chloride ($\text{Cl}^-$): 1(+2) + 2(-1) = 0

$\text{SrCl}_2$

1. Sodium ($\text{Na}^+$) + Sulfide ($\text{S}^{2-}$): 2(+1) + 1(-2) = 0

$\text{Na}_2\text{S}$

1. Radium ($\text{Ra}^{2+}$) + Bromide ($\text{Br}^-$): 1(+2) + 2(-1) = 0

$\text{RaBr}_2$

1. Magnesium ($\text{Mg}^{2+}$) + Sulfide ($\text{S}^{2-}$): charges balance 1:1

$\text{MgS}$

1. Aluminum ($\text{Al}^{3+}$) + Nitride ($\text{N}^{3-}$): charges balance 1:1

$\text{AlN}$

1. Cesium ($\text{Cs}^+$) + Sulfide ($\text{S}^{2-}$): 2(+1) + 1(-2) = 0

$\text{Cs}_2\text{S}$

1. Potassium ($\text{K}^+$) + Chloride ($\text{Cl}^-$): charges balance 1:1

$\text{KCl}$

1. Strontium ($\text{Sr}^{2+}$) + Phosphide ($\text{P}^{3-}$): 3(+2) + 2(-3) = 0

$\text{Sr}_3\text{P}_2$

1. Barium ($\text{Ba}^{2+}$) + Iodide ($\text{I}^-$): 1(+2) + 2(-1) = 0

$\text{BaI}_2$

1. Sodium ($\text{Na}^+$) + Fluoride ($\text{F}^-$): charges balance 1:1

$\text{NaF}$

1. Calcium ($\text{Ca}^{2+}$) + Bromide ($\text{Br}^-$): 1(+2) + 2(-1) = 0

$\text{CaBr}_2$

1. Beryllium ($\text{Be}^{2+}$) + Oxide ($\text{O}^{2-}$): charges balance 1:1

$\text{BeO}$

1. Strontium ($\text{Sr}^{2+}$) + Sulfide ($\text{S}^{2-}$): charges balance 1:1

$\text{SrS}$

1. Boron ($\text{B}^{3+}$) + Fluoride ($\text{F}^-$): 1(+3) + 3(-1) = 0

$\text{BF}_3$

1. Aluminum ($\text{Al}^{3+}$) + Phosphide ($\text{P}^{3-}$): charges balance 1:1

$\text{AlP}$

1. Rubidium ($\text{Rb}^+$) + Oxide ($\text{O}^{2-}$): 2(+1) + 1(-2) = 0

$\text{Rb}_2\text{O}$

1. Calcium ($\text{Ca}^{2+}$) + Iodide ($\text{I}^-$): 1(+2) + 2(-1) = 0

$\text{CaI}_2$

1. Cesium ($\text{Cs}^+$) + Oxide ($\text{O}^{2-}$): 2(+1) + 1(-2) = 0

$\text{Cs}_2\text{O}$

1. Magnesium ($\text{Mg}^{2+}$) + Iodide ($\text{I}^-$): 1(+2) + 2(-1) = 0

$\text{MgI}_2$

1. Lithium ($\text{Li}^+$) + Chloride ($\text{Cl}^-$): charges balance 1:1

$\text{LiCl}$

Answer:

1. $\text{MgO}$
2. $\text{LiBr}$
3. $\text{Ca}_3\text{N}_2$
4. $\text{Al}_2\text{S}_3$
5. $\text{KI}$
6. $\text{SrCl}_2$
7. $\text{Na}_2\text{S}$
8. $\text{RaBr}_2$
9. $\text{MgS}$
10. $\text{AlN}$
11. $\text{Cs}_2\text{S}$
12. $\text{KCl}$
13. $\text{Sr}_3\text{P}_2$
14. $\text{BaI}_2$
15. $\text{NaF}$
16. $\text{CaBr}_2$
17. $\text{BeO}$
18. $\text{SrS}$
19. $\text{BF}_3$
20. $\text{AlP}$
21. $\text{Rb}_2\text{O}$
22. $\text{CaI}_2$
23. $\text{Cs}_2\text{O}$
24. $\text{MgI}_2$
25. $\text{LiCl}$