naming chemical compounds: a review ionic compounds covalent compounds

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Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

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Page 1: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Chemical Compounds:

A Review

Ionic Compounds

Covalent Compounds

Page 2: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Classifying Compounds

The system for naming an ionic compound is different from that for naming a covalent compound, so before a compound can be named, it must be classified as ionic or covalent.

Classifying a compound is not an easy task, but for the purposes of naming them, we employ a simple test:

If the answer is yes, use the system for naming ionic compounds.

If the answer is no, use the system for naming covalent compounds.

Is there a metal or a polyatomic ion present?

Page 3: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Predicting Charges on Monatomic IonsPredicting Charges on Monatomic IonsKNOW THESE !!!!KNOW THESE !!!!

+1 +2 -3 -2 -1 0

Cd+2

Page 4: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Ionic Compounds1. Name the cation 2. Name the anion, drop the ending,

add ide

CaFCaF22

MgMg33NN22

magnesium nitridemagnesium nitride

KK22O O

potassium oxidepotassium oxide

calcium fluoridecalcium fluoride

Page 5: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Learning Check

Complete the names of the following binary compounds:

Na3N sodium ________________

KBr potassium ________________

Al2O3 aluminum ________________

MgS _________________________

nitride

bromide

oxide

magnesium sulfide

Page 6: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Name these Binary Ionic Compounds

NaCl

ZnI2

Al2O3

BeS

LiBr

K3P

sodium chloride

zinc iodide

aluminum oxide

beryllium sulfide

lithium bromide

potassium phosphide

Page 7: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Ionic CompoundsTransition Metals

There are, however, two complicating factors:

I. Some metals form more than one ion.

II. Identifying polyatomic ions

I. Metals that form more than one ion, such as iron, add a Roman numeral to the name to indicate the charge:

Fe2+ is called iron (II) and Fe3+ is called iron (III)

Assume a Roman numeral is required for any metal except

1. metals in groups IA and IIA on the periodic table

2. aluminum, cadmium, silver, and zinc

Page 8: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Ionic Compounds (continued)

If a Roman numeral is required, the charge on the metal ion must be

determined from the charge on the negative ion.

Page 9: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Examples:

CrO Since we know that O is a -2 charge, Cr must be a +2 to balance it out .

Chromium (II) oxide

FeCl3 Since we know that Cl is a -1 charge, Fe must be a +3 to balance it out.

Iron (III) chloride

Page 10: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Learning Check

Complete the names of the following binary

compounds with variable metal ions:

FeBr2 iron (_____) bromide

CuCl copper (_____) chloride

SnO2 ___(_____ ) ______________

Fe2O3 ________________________

Hg2S ________________________

II

I

tin IV oxide

iron (III) oxide

mercury (I) sulfide

Page 11: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Now complete these…

FeCl2iron (II) chloride

Fe2O3iron (III) oxide

PbS2 lead (IV) sulfide

Cu3N copper (I) nitride

Cl has a 1- charge, and there are 2 of them for a total of 2-, so the Fe must be 2+

O has a 2- charge, and there are 3 of them for a total of 6-, so the Fe must have a total charge of 6+ split equally between the two iron atoms, so each must have a 3+ charge

S has a 2- charge, and there are 2 of them for a total of 4-, so the Pb must be 4+

N has a 3- charge, so the Cu must have a total charge of 3+ split equally between the 3 copper atoms, so each must have a 1+ charge

Page 12: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Polyatomic ions

POPO443-3-

phosphate ionphosphate ion

CC22HH33OO22--

acetate ionacetate ion

HC2H3O2

Acetic Acid

NONO33-1-1

nitrate ionnitrate ion

NONO22-1-1

nitrite ionnitrite ion

Page 13: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Ionic Compounds (continued)

I. Polyatomic ions each have specific names which must be memorized so they can be recognized on sight.

Formula Name

C2H3O21- acetate

CO32- carbonate

HCO31- bicarbonate

NH41+ ammonium

A few of the more common polyatomic ions

Formula Name

NO31- nitrate

OH1- hydroxide

PO43- phosphate

SO42- sulfate

With Polyatomic Ions

1. Name the + ion or polyatomic ion

2. Name the – ion or polyatomic ion

Page 14: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

IONIC COMPOUNDSIONIC COMPOUNDS

NH4+1

Cl-1

ammonium chlorideammonium chlorideNHNH44ClCl

Page 15: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Ionic Compounds with Polyatomic Ions: name these…

Na2SO4 sodium sulfate

Fe(NO3)2 iron (II) nitrate

Al2(CO3)3 aluminum carbonate

Pb(OH)4 lead (IV) hydroxide

(NH4)3PO4 ammonium phosphate

MgNO2 magnesium nitrite

C2H3O21- acetate

CO32- carbonate

HCO31- bicarbonate

NH41+ ammonium

NO31- nitrate

OH1- hydroxide

PO43- phosphate

SO42- sulfate

* Groups I & II, Al, Zn, Cd, and Ag need no Roman numeral.

AgC2H3O2 silver acetate

Page 16: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Molecular Compounds

CH4 methaneBCl3 boron trichloride

CO2 Carbon dioxide

All are formed from two or more nonmetals.

Ionic compounds generally involve a metal and nonmetal (NaCl)

Page 17: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Molecular (Covalant) Compounds

Covalent compounds are named by adding prefixes to the element names.

The compounds named in this way are binary covalent compounds.

‘Binary’ means that only two atom are present.

‘Covalent’ (in this context) means both elements are nonmetals.

• The first element is given a prefix ONLY if there is more than one atom of the element. (Do not use mono)

• The second element is ALWAYS given a prefix, and ends in –ide.

Page 18: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Covalent Compounds

Prefixes

Subscript Prefix

1 mono-

2 di-

3 tri-

4 tetra-

5 penta-

Subscript Prefix

6 hexa-

7 hepta-

8 octa-

9 nona-

10 deca-

Note: When a prefix ending in ‘o’ or ‘a’ is added to ‘oxide’, the final vowel in the prefix is dropped.

Page 19: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Learning Check

Fill in the blanks to complete the following names of covalent compounds.

CO carbon ______oxide

CO2 carbon _______________

PCl3 phosphorus _______chloride

CCl4 carbon _____________

N2O _____nitrogen _____oxide

1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 heptaa

8 octa

9 nona

10 deca

* Second element in ‘ide’ from

* Drop –a & -o before ‘oxide’

mon

dioxide

tritetrachloride

di mon

Page 20: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Binary Covalent Compoundstry these…

N2S4 dinitrogen tetrasulfide

NI3 nitrogen triiodide

XeF6 xenon hexafluoride

CCl4 carbon tetrachloride

P2O5 diphosphorus pentoxide

SO3 sulfur trioxide

1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 heptaa

8 octa

9 nona

10 deca

* Second element in ‘ide’ from

* Drop –a & -o before ‘oxide’

Page 21: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Naming Compounds: Practice

SiF4 silicon tetrafluoride

Na2CO3 sodium carbonate

N2O dinitrogen monoxide

K2O potassium oxide

Cu3PO4 copper (I) phosphate

CoI3 cobalt (III) iodide

Analysis If “Yes”

* Is the cation a metal? (If so, does it need a Roman numeral?

The compound is ionic: name

each ion present

(DO NOT USE

PREFIXES)* Is there a

polyatomic ion present?

* Are both elements nonmetals?

The compound is covalent:

use prefixes (NO

CHARGES EXIST)

PI3 phosphorus triiodide

two nonmetals covalent use prefixes

metal present ionic no prefixesNa group I no Roman numeral

two nonmetals covalent use prefixes

metal present ionic no prefixesK group I no Roman numeral

metal present ionic no prefixesCu not group I, II, etc. add Roman numeral (PO4 is 3-, each Cu must be 1+)

metal present ionic no prefixesCo not group I, II, etc. add Roman numeral (I is 1-, total is 3-, Co must be 3+)

two nonmetals covalent use prefixes

NH4Cl potassium oxideNH4 polyatomic ion present ionic no prefixes

Page 22: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Chemical Formulas: A Review

Ionic Compounds

Covalent Compounds

Page 23: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Classifying Compounds

Classifying a compound using its name is not as difficult as using its formula.

The names of covalent compounds will be easily recognized by the presence of the prefixes (mono-, di-, tri-, etc.).

If no prefixes are present in the name, the compound is ionic. (Exception: some polyatomic ion names always contain prefixes (such as dichromate) but those will be memorized and recognized as ions.)

Page 24: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Formulas for Ionic CompoundsFormulas for ionic compounds are written by balancing the

positive and negative charges on the ions present.

Write the formula for the ionic compound that will form between Ba2+ and Cl.

Solution:

1. Balance charge with + and – ions

2. Write the positive ion of metal first, and the

negative ion Ba2+ Cl

Cl3. Write the number of ions needed as

subscripts BaCl2

Page 25: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Learning Check

Write the correct formula for the compounds containing the following ions:

1. Na+, S2-

a) NaS b) Na2S c) NaS2

2. Al3+, Cl-

a) AlCl3 b) AlCl c) Al3Cl

3. Mg2+, N3-

a) MgN b) Mg2N3 c) Mg3N2

Page 26: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Solution

1. Na+, S2-

b) Na2S

2. Al3+, Cl-

a) AlCl3

3. Mg2+, N3-

c) Mg3N2

Page 27: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Formulas for Ionic Compounds (continued)

Helpful Rules to Remember

Name Reasoning Formula

ammonium sulfateNH4 has a 1+ charge & SO4 has a 2- charge, so 2 ammonium ions are required for each sulfate.

(NH4)2SO4

zinc chlorideZn has a 2+ charge & Cl has a 1- charge, so 2 chloride ions are required for each zinc ion.

ZnCl2

copper (II) phosphateCu has a 2+ charge & PO4 has a 3- charge, so 3 copper (II) ions are required for every two phosphate ions.

Cu3(PO4)2

Examples

A metal ion is always positive. The Roman numeral indicates the charge, not the subscript.

The positive and negative charges must cancel (total charge must = 0).If more than one polyatomic ion is needed, put it in parentheses, and place a subscript outside the parentheses.

Page 28: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Learning Check

1. aluminum nitrate

a) AlNO3 b) Al(NO)3 c) Al(NO3)3

2. copper(II) nitrate

a) CuNO3 b) Cu(NO3)2 c) Cu2(NO3)

3. Iron (III) hydroxide

a) FeOH b) Fe3OH c) Fe(OH)3

4. Tin(IV) hydroxide

a) Sn(OH)4 b) Sn(OH)2 c) Sn4(OH)

Page 29: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

1. Copper (II) chlorate

2. Calcium nitride

3. Aluminum carbonate

4. Potassium bromide

5. Barium fluoride

6. Cesium hydroxide

Write the formula:

Page 30: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Formulas for Covalent Compounds

The names of covalent compounds contain prefixes that indicate the number of atoms of each element present.

Remember: The compounds named in this way are binary covalent compounds (they contain only two elements, both of which are nonmetals). When in covalent compounds, atoms do not have charges. Subscripts are determined directly from the prefixes in the name.

If no prefix is present on the name of the first element, there is only one atom of that element in the formula (its subscript will be 1).

A prefix will always be present on the name of the second element. The second element will use the form of its name ending in ide.

Page 31: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Formulas for Binary Covalent CompoundsTry these…

nitrogen dioxide NO2

diphosphorus pentoxide P2O5

xenon tetrafluoride XeF4

sulfur hexafluoride SF6

1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 heptaa

8 octa

9 nona

10 deca

* Second element in ‘ide’ from

* Drop –a & -o before ‘oxide’

Page 32: Naming Chemical Compounds: A Review Ionic Compounds Covalent Compounds

Writing Formulas: Practice

carbon tetrafluoride CF4

Na3PO4sodium phosphate

Cu2SO4copper (I) sulfate

Analysis If “Yes”

The compound is covalent: the prefixes give

the subscripts.

* Are there prefixes present

The compound

is ionic: subscripts must be

determined by

balancing charges

prefixes covalent prefixes indicate subscripts

metal ionic balance charges 3 Na1+ needed for 1 PO43-

metal present ionic balance charges 2 Cu1+ needed for 1 SO42-

Al2S3aluminum sulfidemetal present ionic balance charges 2 Al3+ needed for 3 S2-

N2O5dinitrogen pentoxideprefixes covalent prefixes indicate subscripts

NH4NO3ammonium nitratepolyatomic ion present ionic balance charges

1 NH41+ needed for 1 NO3

1-

PbO2lead (IV) oxidemetal present ionic balance charges 1 Pb4+ needed for 2 O2-

Fe2(CO3)3 iron (III) carbonatemetal present ionic balance charges 2 Fe3+ needed for 3 CO3

2-