Question

sa 3 writing chemical formulas
write the chemical formulas for the following compounds:

1. sodium hydride
2. gallium (iii) hydrogen sulfide
3. potassium arsenide
4. gold (i) carbonate
5. krypton hexabromide
6. manganese (ii) nitride
7. mercury (ii) sulfide
8. zinc phosphide
9. nickel (ii) borate
10. ammonium oxalate
11. titanium (iv) carbide
12. barium arsenide
13. tetraarsenic trisulfide
14. tantalum (v) hydrogen sulfite
15. aluminum iodide
16. hydrogen ditelluride
17. cadmium chloride
18. cesium phosphate
19. germanium (iv) selenide
20. disulfur dinitride
21. heptasulfur dioxide
22. silver citrate
23. rhenium (vii) carbonate
24. magnesium thiosulfate

Explanation:

Step1: Determine ion charges

Use common - ion charges and oxidation states to write chemical formulas. For example, sodium has a + 1 charge ($Na^+$) and hydride has a - 1 charge ($H^-$).

Step2: Balance charges

Combine ions in ratios to balance the overall charge of the compound.

1. Sodium hydride: $Na^+$ and $H^-$ combine to give $NaH$.
2. Gallium (III) has a + 3 charge ($Ga^{3 + }$) and hydrogen sulfide ion ($HS^-$), so the formula is $Ga(HS)_3$.
3. Potassium has a + 1 charge ($K^+$) and arsenide has a - 3 charge ($As^{3 - }$), the formula is $K_3As$.
4. Gold (I) has a + 1 charge ($Au^+$) and carbonate has a - 2 charge ($CO_3^{2 - }$), the formula is $Au_2CO_3$.
5. Krypton hexabromide: Krypton is a noble - gas, but here it forms a compound with bromine. Krypton has an oxidation state of + 6 and bromine has a - 1 charge ($Br^-$), the formula is $KrBr_6$.
6. Manganese (II) has a + 2 charge ($Mn^{2+}$) and nitride has a - 3 charge ($N^{3 - }$), the formula is $Mn_3N_2$.
7. Mercury (II) has a + 2 charge ($Hg^{2+}$) and sulfide has a - 2 charge ($S^{2 - }$), the formula is $HgS$.
8. Zinc has a + 2 charge ($Zn^{2+}$) and phosphide has a - 3 charge ($P^{3 - }$), the formula is $Zn_3P_2$.
9. Nickel (II) has a + 2 charge ($Ni^{2+}$) and borate ($BO_3^{3 - }$), the formula is $Ni_3(BO_3)_2$.
10. Ammonium has a + 1 charge ($NH_4^+$) and oxalate has a - 2 charge ($C_2O_4^{2 - }$), the formula is $(NH_4)_2C_2O_4$.
11. Titanium (IV) has a + 4 charge ($Ti^{4+}$) and carbide has a - 4 charge ($C^{4 - }$), the formula is $TiC$.
12. Barium has a + 2 charge ($Ba^{2+}$) and arsenide has a - 3 charge ($As^{3 - }$), the formula is $Ba_3As_2$.
13. Tetraarsenic trisulfide: Arsenic and sulfur combine. The prefixes indicate the number of atoms. The formula is $As_4S_3$.
14. Tantalum (V) has a + 5 charge ($Ta^{5+}$) and hydrogen sulfite ($HSO_3^-$), the formula is $Ta(HSO_3)_5$.
15. Aluminum has a + 3 charge ($Al^{3+}$) and iodide has a - 1 charge ($I^-$), the formula is $AlI_3$.
16. Hydrogen has a + 1 charge ($H^+$) and telluride has a - 2 charge ($Te^{2 - }$), the formula is $H_2Te$.
17. Cadmium has a + 2 charge ($Cd^{2+}$) and chloride has a - 1 charge ($Cl^-$), the formula is $CdCl_2$.
18. Cesium has a + 1 charge ($Cs^+$) and phosphate has a - 3 charge ($PO_4^{3 - }$), the formula is $Cs_3PO_4$.
19. Germanium (IV) has a + 4 charge ($Ge^{4+}$) and selenide has a - 2 charge ($Se^{2 - }$), the formula is $GeSe_2$.
20. Disulfur dinitride: The prefixes indicate 2 sulfur and 2 nitrogen atoms, the formula is $S_2N_2$.
21. Heptasulfur dioxide: The prefixes indicate 7 sulfur and 2 oxygen atoms, the formula is $S_7O_2$.
22. Silver has a + 1 charge ($Ag^+$) and citrate ($C_6H_5O_7^{3 - }$), the formula is $Ag_3C_6H_5O_7$.
23. Rhenium (VII) has a + 7 charge ($Re^{7+}$) and carbonate ($CO_3^{2 - }$), the formula is $Re_2(CO_3)_7$.
24. Magnesium has a + 2 charge ($Mg^{2+}$) and thiosulfate has a - 2 charge ($S_2O_3^{2 - }$), the formula is $MgS_2O_3$.

Answer:

1. $NaH$
2. $Ga(HS)_3$
3. $K_3As$
4. $Au_2CO_3$
5. $KrBr_6$
6. $Mn_3N_2$
7. $HgS$
8. $Zn_3P_2$
9. $Ni_3(BO_3)_2$
10. $(NH_4)_2C_2O_4$
11. $TiC$
12. $Ba_3As_2$
13. $As_4S_3$
14. $Ta(HSO_3)_5$
15. $AlI_3$
16. $H_2Te$
17. $CdCl_2$
18. $Cs_3PO_4$
19. $GeSe_2$
20. $S_2N_2$
21. $S_7O_2$
22. $Ag_3C_6H_5O_7$
23. $Re_2(CO_3)_7$
24. $MgS_2O_3$