1. Unit 6B: Naming and Writing Formulas for Ionic and Covalent Compounds

2. Polyatomic Ions Polyatomic ions are groups of atoms that are covalently bonded and have a charge. PO 4 3- = phosphate ion SO 4 2- = sulfate ion

3. Polyatomic Ions Ending of –ate or –ite means there are oxygen atoms in the formula of the ion. SO 4 2- = sulfate SO 3 2- = sulfite

4. Polyatomic Ions The –ate ending always has one more oxygen than the –ite ending. SO 4 2- = sulfate NO 3 - = nitrate SO 3 2- = sulfiteNO 2 - = nitrite

5. Names for Cations and Anions Monatomic Cation Names: Same as element name Na +  sodium ion Al 3+  aluminum ion

6. Names for Cations and Anions What about transition metals with more than one charge? Fe 2+  iron(II) Fe 3+  iron(III)

7. Names for Cations and Anions What about transition metals with more than one charge? Cu +  copper(I) Cu 2+  copper(II)

8. Names for Cations and Anions Monatomic Anion Names: Element name with – ide ending S 2-  sulfide ion O 2-  oxide ion

9. Names for Cations and Anions Monatomic Anion Names: Element name with – ide ending P 3-  phosphide ion N 3-  nitride ion

10. Naming Binary Ionic Compounds A binary compound is composed of two elements and can be ionic or molecular (covalent). Binary ionic compound = metal, then nonmetal

11. Naming Binary Ionic Compounds NaCl sodium chloride Ca 3 P 2 calcium phosphide CuCl 2 copper(II) chloride Ni 3 N 2 nickel(II) nitride

12. Naming Compounds with Polyatomic Ions To name an ionic compound with a polyatomic ion, write the name of the cation first, followed by the name of the anion.

13. Naming Compounds with Polyatomic Ions NaNO 3 sodium nitrate (NH 4 ) 2 SO 4 ammonium sulfate Ca(NO 3 ) 2 calcium nitrate

14. Writing Formulas for Ionic Compounds The metal (cation) always goes first, followed by the nonmetal (anion).

15. Writing Formulas for Ionic Compounds Use the “criss-cross method” to balance out the charges.

16. Writing Formulas for Ionic Compounds Use the “criss-cross method” to balance out the charges. Parenthesis must be used if more than one polyatomic ion is needed.

17. Writing Formulas for Ionic Compounds Use the “criss-cross method” to balance out the charges. Always reduce the subscripts to lowest terms

18. Naming Binary Molecular Compounds We use prefixes to tell how many of each element are in a binary molecular compound.

19. Naming Binary Molecular Compounds Name the elements in the order listed in the compound, using prefixes to indicate the number of each element. Never use the prefix mono- for the first element The second element always ends in -ide

20. Naming Binary Molecular Compounds CO carbon monoxide CO 2 carbon dioxide P 4 O 10 tetraphosphorus decoxide N2O5N2O5 dinitrogen pentoxide

21. Writing Formulas for Binary Molecular Compounds Write the formula in the same order the elements are named. The prefix tells you the subscript for each element.

22. Writing Formulas for Binary Molecular Compounds Dioxygen monofluoride O 2 F Phosphorus trichloride PCl 3

23. Review Binary Ionic Compounds Binary Molecular Compounds ElectronsGive and TakeShared Type of ElementsMetal + NonmetalNonmetal + Nonmetal NamingNO prefixesYES prefixes YES Roman numerals (if > 1 charge)NO Roman numerals

24. Review