1. Naming Chemical Compounds

2. Review What is a chemical formula?
shorthand representation of the composition of a substance using atomic symbols and numerical subscripts
can represent a molecule (covalent bonded structure) or a formula unit (ionic bonded structure)

3. Review Significance of a chemical formula
formula tells number and type of atoms in a molecule or formula unit (one atom difference can cause change in properties)
Examples: Ag, NaCl, HCl, Al2(SO4)3, CaSO4  5 H2O, etc.

4. Naming Ionic Compounds
Binary ionic compounds
Metal named first
Name of non-metal has –ide added
If metal has more than one possible charge use stock system (Roman numerals) or common name
Ex: NaCl, KI, FeF2, FeF3

5. Naming Ionic Compounds
Compounds with polyatomic ions
Cation is named first (using stock or common name)
Anion is named second (using name of polyatomic ion)
Al2(CO3)3, BaSO4, CaSO3, Fe(NO3)2, NH4Cl
(DO NOT change endings of polyatomic ions!!!)

6. Naming Ionic Compounds
Hydrates
ionic compounds that absorb water into their structures
named like regular ionic compounds, add numeric prefix and hydrate at the end

7. Naming Ionic Compounds
Prefixes:
1: mono-
2: di-
3: tri-
4: tetra-
5: penta-
6: hexa-
7: hepta-
8: octa-
9: nona-
10: deca-

8. Naming Ionic Compounds
Hydrates
ionic compounds that absorb water into their structures
named like regular ionic compounds, add numeric prefix and hydrate at the end
MgSO4  7 H2O, CuSO4  5 H2O

9. Naming Molecular Compounds
Binary molecular compounds
Element from left-most part of table is named first
Name of second element has –ide added
Use Greek prefixes to indicate number of atoms

10. Naming Molecular Compounds
Prefixes:
1: *mono-
(*only with second element)
2: di-
3: tri-
4: tetra-
5: penta-
6: hexa-
7: hepta-
8: octa-
9: nona-
10: deca-

11. Naming Molecular Compounds
Binary molecular compounds
Element from left-most part of table is named first
Name of second element has –ide added
Use Greek prefixes to indicate number of atoms
CO, CCl4, N2O, N2O3

12. Naming Molecular Compounds
Acids
when in water, produce H+ ions, name usually from characteristic anion
Hydro acids: hydro + name of halogen + -ic + acid
HCl, HF, HBr
Oxoacids: polyatomic ion + acid (use –ous and –ic as needed, -ic goes with > # O atoms)
H2SO4, HNO2, HNO3

13. Naming Chemical Compounds
Given: Chemical Formula
Wanted: Name of Compound
Need to ask questions to determine which naming rules to use
Here is one set of questions you could use…

14. Has a metal?
Yes No No
Yes No
Yes
Yes No
Yes No

15. Writing Formulas
Use the criss-cross method – the charges (superscripts) go to the bottom (as subscripts) and switch from right to left

16. Writing Formulas Examples: Fe3+ + Cl1- becomes Al3+ + O2- becomes
Sn2+ + O2- becomes
Mg2+ + (OH)1- becomes
NH41+ + SO42- becomes
FeCl3
Al2O3
SnO
Mg(OH)2
(NH4)2SO4

17. Writing Formulas
Remember: you are looking for the smallest whole-number ratio of ions that will give an overall charge of 0 – that’s why the 3rd example has no subscripts ( = 0)