CHAPTER 5 NAMING COMPOUNDS

UNDERSTNDING 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

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)

What are the rules for naming acids????

#1 Does the acid contain an oxygen in the formula????

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

EXAMPLE

HCl dissolved in water = no oxygen therefore…….HYDROchlorIC acid

HCN disssolved in water = hydrocyanic acid

H2S dissolved in water = hydrosulfuric acid

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

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 + ______=

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 2. Na and Br 7. H and H

3. O and Cl 4. Fe and Fe 8. H and Cl

5. Zn and Zn 6. O and F

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 / NUMBER
Mono / 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 Covalnet Formulas

No “criss cross” - write exactly as written

Trichlorine pentaoxide ______

Nitrogen octahydride ______

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)

A. 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)

Do this process “in reverse” and criss cross the charges (oxidation numbers)

Na + Cl = ______

Magnesium fluoride = + = ______

Calcium oxide = + = ______

N + Li = ______

**why is lithium written before nitrogen?

The positive ion is called a cation and is always written first

The negative ion is called an anion and is written second.

** in other words the Cation (usually the metal) 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 who they are paired with

*because they vary we need to figure out and then write down their oxidation number

b. we use use roman numerals or numbers to do this

I = one II = two III = three IV = four

B. 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

MnO2 Manganses (IV) oxide

Practice

Cr (+4) + O = ______

Fe3O2 = ______

ZnCl2 = ______

CuO = ______

Writing Ionic Formulas (with transition metals)

Figure out the symbols and “criss cross” the charges

Zinc (II) fluoride ______+ ______= ______

Nickle (I) acetate ____ + ______= ______

Gold (III) cyanide ______+ ______= ______

Copper (II) nitrite _____ + ______= ______

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 +1
Acetate / 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 ______+ ______= ______