CHAPTER 5 NAMING COMPOUNDS
UNDERSTANDING CHEMICAL FORMULAS
General information
The formula tells the elements that make up a compound and the number of atoms of each element in the compound.
-when a subscript is written outside of a set of parentheses, there are multiples of those groups
Example
FeCl2 There is 1 iron atom for every 2 chlorine atoms
Mg3(PO4)2 There are 3 total magnesium atoms for every 2 GROUPS of PO4 compounds
Practice
BeF there are _____ beryllium atoms for every ______fluorine atoms
Cu2(CrO4)3 there are ____ copper atoms for every ______chromate compounds
DETERMINING BOND TYPE-
A. Ionic bonds- bonds between a metal and a nonmetal – ex NaCl
B. Covalent bonds- bonds between two nonmetals - ex H2O
C. Metallic bonds-bonds between two atoms of same metal- ex Cu
D. Practice
1. Mg and F _____ 4. Na and Br _____ 7. H and H _____
2. O and Cl _____ 5. Fe and Fe _____ 8. H and Cl _____
3. Zn and Zn _____ 6. O and F _____
NAMING IONIC FORMULAS
What does an ionic compound look like?????
It is a compound with a bond between a metal and a non-metal
What are the rules for naming ionic compounds?? (with no transition metals)
Binary Ionic Compounds (metals from Group 1 or 2) (ex: CaCl2)
1. Name the metal
2. Name the nonmetal-
a. change ending to –ide
3. CaCl2 = calcium chloride
EXAMPLE
a. KCl potassium chloride
b. LiF lithium fluoride
c. Na2O sodium oxide
Ionic Practice (no transition metals)
CaO ______NaCl ______
MgF2 ______RbBr ______
Writing Ionic Formulas (with no transition metal)
Criss-cross the charges (oxidation numbers)
Na + Cl = ______
Magnesium fluoride = + = ______
Calcium oxide = + = ______
N + Li = ______
**why is lithium written before nitrogen? The cation is always written first
What are the rules for naming ionic compounds?? (with transition metals)
*Transition metals work a differently because they vary their valence electrons.
Figure out oxidation number of transition metals by looking at what they are paired with
*We use roman numerals to do this: I = one II = two III = three IV = four
*Side note: assume Zinc = +2 and Silver = +1 unless otherwise indicated
(most common for our purposes)
Transitions metals
Binary Ionic Compounds (transition metals) (ex: Fe2O3)
1. Name the metal
2. Transition metals have more than one + charge (ex:iron can have +2 or +3)
a. determine the charge of nonmetal
***helpful hint – the TOTAL charge must always = 0
Fe O
b. Figure out the total - charge on “non-metal” side, then set the total metal equal to the + charge
3. After the name of metal, write charge in roman numerals. {put in ( )}
Fe +3 = iron (III)
4. Name the nonmetal. Change ending to –ide
5. Fe2O3 = Iron(III)oxide
EXAMPLES
NiS Nickel (II) sulfide
FeF3 Iron (III) fluoride
AgCl Silver (I) chloride
Practice
Cr (+4) + O = ______
Fe2O3 = ______
ZnCl2 = ______
CuO = ______
MnO2 = ______
Writing Ionic Formulas (with transition metals)
Figure out the symbols and “criss cross” the charges
Zinc (II) fluoride ______+ ______= ______
Nickle (I) oxide ____ + ______= ______
Gold (III) chloride ______+ ______= ______
Copper (II) nitride _____ + ______= ______
NAMING COMPOUNDS WITH POLYATOMICS …… Poly = many
General Information
Polyatomic ions are made of covalently bonded atoms that tend to stay together and act as if they were single atoms
a. therefore bonds WITHIN polyatomic ions = covalent
b. but they usually form ionic bonds with other atoms
What does a polyatomic look like? Since we are only naming binary compounds, any compound that has more than 2 capital letters has a polyatomic in it & almost all polyatomics end with something other then “IDE”
Some of the common polyatomics and their charge
Ammonium / NH4 +1Acetate / C2H3O2 -1
Chlorate / ClO3 -1
Hydrogen carbonate / HCO3 -1
Hydroxide / OH -1
Nitrite / NO2 -1
Nitrate / NO3 -1
Carbonate / CO3 -2
Sulfate / SO4 -2
Sulfite / SO3 -2
Phosphate / PO4 -3
Rules for naming compounds with polyatomic ions
Follow the previous rules for naming IONIC compounds (with and without transition metals) BUT do not change the polyatomic ending
EXAMPLE
Mg(OH)2 magnesium hydroxide
CuSO4 copper (II) sulfate
Zn(NO3)2 Zinc (II) nitrate
K2CO3 potassium carbonate
Practice
Na2CO3 ______
Ca(ClO3)2 ______
Ca(OH)2 ______
K3PO3 ______
MnSO3 ______
Writing formulas for compounds with polyatomics
Figure out the symbols and “criss cross” the charges
Lead (II) hydroxide ______+ ______= ______
Beryllium phosphate _____ + ______= ______
Copper (II) carbonate ______+ ______= ______
Silver (I) permanganate ______+ ______= ______
NAMING COVALENT COMPOUNDS
What does a covalent compound look like???
It is a compound with a bond between a nonmetal and a nonmetal
What are the rules for naming covalent compounds???
Use prefixes to name covalent compounds, change ending of second compound to “ide”
1. Use same ending as most ionic compounds…….ide
1. Covalent Bonding requires Prefixes
a. prefixes tell you how many of each atom there are in the compound
b. you cannot start any covalent compound with the word mono
PREFIX / NUMBERMono / 1
Di / 2
Tri / 3
Tetra / 4
Penta / 5
Hexa / 6
Hepta / 7
Octa / 8
Nona / 9
Deca / 10
Examples
N2O4 Dinitrogen tetraoxIDE
H2O Dihydrogen monoxIDE
BF3 Boron trifluorIDE **notice no mono to start name!!
Covalent Practice
SiO2 ______CO2 ______
CO ______P2O5 ______
Writing Covalent Formulas
No “criss cross” - write exactly as written
Trichlorine pentaoxide ______
Nitrogen octahydride ______
NAMING ACIDS
General information on acids
-When dissolved in water, certain molecules produce H+ ions. These substances are called acids.
-An acid can be viewed as a molecule with one or more H+ ions attached to an anion (negatively charged atom).
What does an acid compound look like????
Look for a compound that has the H atom first and is connected to something else (an anion) (except for oxygen)
Rules for naming acids
#1 Does the acid contain an oxygen in the formula????
a. If the anion DOES NOT CONTAIN OXYGEN, the acid is named with the prefix “hydro” and the suffix “ic” is attached to the root name for the element
EXAMPLE
HCl dissolved in water = no oxygen therefore…….HYDROchlorIC acid
HCN disssolved in water = hydrocyanic acid
H2S dissolved in water = hydrosulfuric acid
b. If the anion DOES CONTAIN OXYGEN, the acid name is formed from the root name of the central element of the anion with a suffix of “ic” or “ous”.
i. When the anion name ends in “ate” the suffix “ic” is used.
ii. When the anion name ends in “ite” the suffix “ous” is used
EXAMPLE (for anions with ate ending)
H2SO4 dissolved in water = the anion is sulfate so…….sulfuric acid
H3PO4 dissolved in water = the anion is phosphate so…. phosphoric acid
HC2H3O4 = anion is acetate so…………acetic acid
EXAMPLE:
H2SO3 = anion is sulfite so …….. sulfurous acid
HNO2 = anion is nitrite so……. Nitrous acid
ACID PRACTICE:
H3PO4 ______
H3PO3 ______
HF ______
HCl ______
Writing acid formulas
Do this process “in reverse” and criss-cross the charges (oxidation numbers)
Hydrochloric Acid H + Cl =
Sulfurous Acid H + ______=
Phosphoric Acid H + ______=
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Flowchart: How to Name Compounds
Is it an Acid?
Yes / NoDoes the acid contain an oxygen in the formula?
1.If the anion DOES NOT CONTAIN OXYGEN, the acid is named with the prefix “hydro-” and the siffix “-ic” is attached to the root name for the element
2. If the anion DOES CONTAIN OXYGEN, the acid name is formed from the root name of the central element of the anion with a suffix of “-ic” or “-ous”. When the anion name ends in “-ate” the suffix “-ic” is used. When the anion name ends in -ite the suffix “-ous” is used / Covalent Bond
(NM & NM) / Ionic Bond
(M & NM or M & Poly)
1. Name the first element
-add prefix (di, tri, etc.)
-do not add mono to first element
2. Name the second element
-add prefix (mono, di, tri, etc.)
-change ending to –ide / Transition Metal / Other Metals
Polyatomic / No Poly. / Polyatomic / No Poly.
1. Figure out charge on metal
2. Name metal with charge following in
( )
3. Name the poly.
-no ending change / 1. Figure out charge on metal
2. Name metal with charge following in ( )
3. Name the nonmetal
-change ending to -ide / 1. Name the metal
2. Name the poly
-no ending change / 1. Name the metal
2. Name the nonmetal
-change ending to -ide
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