Name: ______Key______Date: ______
Study Guide Chapter 9
Chemical Names and Formulas
How do you name monatomic ions? (Both cations and anions)
The cations would be named the metal ion. For example: the lithium cation (Li+), would be named the lithium ion. Monatomic anions would have an –ide ending. For example: the oxygen anion (O2-) would be named the oxide ion.
Give three examples of polyatomic ions?
CO32- (carbonate) NO2- (nitrite) ClO4- (perchlorate)(Or any others that are listed on page 2 table E of
your reference table)
How do we balance ionic compounds that contain polyatomic ions? What must we add if more than one polyatomic ion is needed to balance a chemical formula?
We use our crisscross method. If more than one polyatomic ion is necessary to cancel out the overall charge of the compound, we must add parenthesis.
If there is more than one oxidation state for a metal, what must we use when naming a compound involving that metal? Give an example using lead as your cation.
If there is more than one oxidation state for a metal, we must use roman numerals in parenthesis when naming. For example, the compound PbO would be named lead(II) oxide while PbO2 would be named lead (IV) oxide. Here’s why: If the compound is PbO and we know that oxygen has a 2- charge when it becomes an ion, than in order for the formula to be PbO lead must have a charge of 2+. If the compound has the formula PbO2 and oxygen has a charge of 2- and there are two oxygens, so in order to cancel out an overall charge of 4-, that one lead must have a charge of 4+.
What similarity is there between naming ionic and molecular compounds? What is different?
When naming both binary ionic and binary molecular compounds, the ending on the second elements name ends in –ide. When naming ionic compounds we don’t use prefixes, but we do use roman numerals in parenthesis when naming an ionic compound whose metal has more than one oxidation state. When naming molecular compounds we use prefixes (but if there is only one atom of the first nonmetal, we don’t use a prefix on that element. If there is more than one, then we do.)
Where can we find names of acids and bases? Based on the chemical formula, how do we know that we are dealing with an acid? Based on the chemical formula, how do we know that we are dealing with a base?
We can find the formulas of many common acids and bases in our reference table, on page 6 (tables K and L). Acids have a H as the first element in their formula, and most bases have an OH group on the end of their formulas.
Name the prefixes used in naming molecular compounds?
NumberPrefixNumberPrefix
1mono- 6hexa-
2di- 7hepta-
3tri- 8octa-
4tetra- 9nona-
5penta- 10deca-
Name the following or give the formula for the following:
CaI2calcium iodide
phosphoruspentafluoridePF5
SnCl4tin(IV) chloride
H3PO4phosphoric acid
perchlorate ClO4-
S2O32-thiosulfate
potassium hydroxide KOH
XeF6xenon hexafluoride
diphosphorus pentachloride P2Cl5
beryllium iodide BeI2
lead(IV) oxide PbO2
A compound of general formula QxRy contains no hydrogen, Q is the metal of lowest atomic mass, and R contains the elements oxygen and carbon in a 3:1 ratio. Write the name and the formula of the compound.
Li2CO3 which is lithium carbonate