Write the formulas for the following ionic compounds: 12. potassium dichromate 13. gold(III) oxide 14. aluminum periodate 15. barium nitrite 16. silver carbonate 17. lithium sulfite 18. zinc hydrogen carbonate 19. iron(III) hydroxide 20. ammonium phosphate 21. copper(II) bromite 22. SO2 23. N2S 24. BF3 25. PBr3 26. SiO2 27. SF6 28. NO2 29. nitrogen trichloride 30. dinitrogen trioxide 31. phosphorus pentafluoride 32. diboron tetrahydride
The Correct Answer and Explanation is:
Here are the correct formulas for each compound:
Ionic Compounds:
- Potassium dichromate – K₂Cr₂O₇
- Gold(III) oxide – Au₂O₃
- Aluminum periodate – Al(IO₄)₃
- Barium nitrite – Ba(NO₂)₂
- Silver carbonate – Ag₂CO₃
- Lithium sulfite – Li₂SO₃
- Zinc hydrogen carbonate – Zn(HCO₃)₂
- Iron(III) hydroxide – Fe(OH)₃
- Ammonium phosphate – (NH₄)₃PO₄
- Copper(II) bromite – Cu(BrO₂)₂
Covalent (Molecular) Compounds:
- SO₂ – sulfur dioxide
- N₂S – dinitrogen monosulfide
- BF₃ – boron trifluoride
- PBr₃ – phosphorus tribromide
- SiO₂ – silicon dioxide
- SF₆ – sulfur hexafluoride
- NO₂ – nitrogen dioxide
- Nitrogen trichloride – NCl₃
- Dinitrogen trioxide – N₂O₃
- Phosphorus pentafluoride – PF₅
- Diboron tetrahydride – B₂H₄
Explanation
Chemical compounds are named using different systems based on the type of bonding. Ionic compounds consist of metals and nonmetals, where electrons are transferred, while covalent (or molecular) compounds consist of nonmetals sharing electrons.
For ionic compounds, the metal forms a cation (positive ion) and the nonmetal or polyatomic group forms an anion (negative ion). The charges must balance to write the correct formula. For example, potassium dichromate is written as K₂Cr₂O₇ because potassium (K⁺) has a +1 charge, and dichromate (Cr₂O₇²⁻) has a -2 charge. Two K⁺ ions are needed to balance one Cr₂O₇²⁻ ion.
In compounds like gold(III) oxide, the Roman numeral indicates the charge on the metal cation (Au³⁺), and oxide is O²⁻, so the formula becomes Au₂O₃.
Covalent compounds use Greek prefixes to indicate the number of atoms. For example, dinitrogen trioxide (N₂O₃) uses “di-” for two nitrogen atoms and “tri-” for three oxygen atoms.
It’s important to note that molecular compounds do not require charge balancing like ionic ones. Sulfur hexafluoride (SF₆) simply means one sulfur atom bonded to six fluorine atoms.
Correct naming and formula writing involve understanding the periodic table, ion charges, and naming conventions, all of which ensure clear communication in chemistry.
