1. Chemical Names and Formulas
Chapter 9
Chemical Names and Formulas

2. Copper Compounds
What is the difference between Cu2O and CuO? Is there any difference?
You may think that there is very little difference between the two, but there is! Naming compounds very specifically is important in order to tell the difference between similar compounds?
Cu2O
Red powder
fungicide
CuO
Black powder
Used in batteries

3. Remeber Naming Ions? What is a cation? How many electrons does Group
Cations – positively charged ion
How many electrons does Group
1,2, and 3 lose?
Groups 1,2, and 3 lose electrons
Group 1 – lose 1 electron
Group 2 – lose 2 electrons
Group 3 – lose 3 electrons

4. Remember Naming Ions? Anion – negatively charged ion
Groups 5,6, and 7 generally gain electrons
Group 5 – gain 3 electrons
Group 6 – gain 2 electrons
Group 7 – gain 1 electron

5. Naming Ions
Transition metals usually lose electrons, how many electrons they lose depends on the element

6. Naming Ions
If you actually think about it, it will make sense why some of the transition elements could have two different ions
Ex: Copper (Cu) forms both a +1 and a +2 cation
Why? (Hint: Use the periodic table and electron configuration.)
+1 cation: Cu = [Ar] 4s1 3d10 – loses 1 from the 4s subshell
+ 2 cation: if Cu does not achieve pseudo-stability, it is [Ar] 4s2 3d9 – will lose the two electrons from the 4s subshell

7. Polyatomic Ions Ions composed of more than 1 atom
You just have to memorize these
Most end in –ite or –ate
-ite tells you there is 1 less oxygen atom than the –ate ending

8. Naming and Writing Formulas for Ionic Compounds
what do ionic compounds contain?
Ionic compounds – contain a metal and a nonmetal
How do we name a binary ionic compound (binary means composed of 2 elements)?
Place the cation name first, then the anion name
Usually add –ide to the end of the anion name

9. Naming and Writing Formulas for Ionic Compounds
What would Cs2O be?
Cesium oxide
NaF?
Sodium fluoride
Cu2O (hint: copper has two possible ions! Which one is it?)
Copper (I) oxide
SnS2
Tin (IV) Sulfide
Mn2O3
Manganese (III) oxide
LiCN
Lithium cyanide
(NH4)2C2O4
Ammonium oxalate (the –ide ending is usually left out if the anion is a polyatomic ion)

10. Naming and Writing Formulas for Ionic Compounds
To write a formula for a binary ionic compound, we need to go back to Ch. 7 and balance the charges
Ex: iron (III) oxide
Fe+3 O-2
Fe2O3
Ca+2 S-2
Ca2S2….reduce to CaS
Remember crisscross the charge and reduce subscripts to the lowest whole number ratio

11. Naming and Writing Formulas for Ionic Compounds
Another way…just think about how you would balance the charges out by finding the least common multiple
K+1 N-3
We need a 3 to balance out the +1 on K (1 x 3 =3) and a 1 to balance out the -3 on N (1 x 3) = 3
So K3N
Ba+2 S-2
Both have a 2 charge, they balance each other out
BaS

12. Naming and Writing Formulas for Ionic Compounds
For polyatomic ions, keep the ion together – balance the overall charge of the ion
Ex: Ca+2 (NO3)-1
Ca(NO3)2
Use parentheses to set off the polyatomic ion only if there is than one of the polyatomic ion
Ex: Li+1 (CO3)-2
Li2CO3 – no parentheses because there is only one polyatomic ion
Ex: NH4+1 (SO3)-2
(NH4)2SO3

13. Naming and Writing Formulas for Molecular Compounds
What is a binary molecular compound?
A compound composed of 2 elements that are both nonmetals – NOT ions
Binary compounds can have 2 elements composed in various ways – ex: CO and CO2 or NO and N2O so we can’t name them like we did with ionic compounds
We need prefixes…prefixes tell us how many atoms of each element are present in each molecule

14. Naming and Writing Formulas for Molecular Compounds
Here are a few hints:
If there is only 1 atom of the first element, omit the prefix mono-
You will usually add the –ide ending to the second element
Ex: CO
Carbon monoxide
Ex: N2O
Dinitrogen monoxide
Ex: Cl2O7
Dichlorine heptoxide
Ex: BCl3
Boron trichloride

15. Naming and Writing Formulas for Molecular Compounds
Use the prefixes of each element to write the formula (hint: -mono is left out of the first element if there is only 1 atom)
Ex: carbon monoxide CO
Ex: carbon tetrabromide
CBr4
Ex: diphosphorus trioxide
P2O3
Ex: iodine heptafluoride
IF7

16. Cation has more than 1 charge
Summarization
Compound
Covalent
nonmetals
Use prefixes + ide
Omit “mono” for first element if there is only one
Ionic
Metal + nonmetal
Cation has one charge
Metal + nonmetal + ide ending
Cation has more than 1 charge
Metal (charge) + nonmetal + ide ending