Naming CompoundsWriting Formulas

Chapter 5

Systematic Naming There are too many compounds to

remember the names of them all. Compound is made of two or more

elements. Put together atoms. Name should tell us how many and

what type of atoms.

Periodic Table More than a list of elements. Put in columns because of similar

properties. Each column is called a group.

2A1A

3A4A5A

6A7A

0Representative elements The group A

elements The tall columns

Metals

Transition metals The Group B

elements

Non-metals Dull Brittle Nonconductors

- insulators

Metalloids or Semimetals Properties of both Semiconductors

Atoms and ions Atoms are electrically neutral. Same number of protons and electrons. Ions are atoms, or groups of atoms,

with a charge. Different numbers of protons and

electrons. Only electrons can move. Gain or lose electrons.

Anion A negative ion. Has gained electrons. Non metals can gain electrons. Charge is written as a superscript on

the right.

F1- Has gained one electron

O2- Has gained two electrons

Cations Positive ions. Formed by losing electrons. More protons than electrons. Metals form cations.

K1+ Has lost one electron

Ca2+ Has lost two electrons

Two Types of Compounds Molecular compounds Made of molecules. Made by joining nonmetal atoms

together into molecules.

Two Types of Compounds Ionic Compounds Made of cations and anions. Metals and nonmetals. The electrons lost by the cation are

gained by the anion. The cation and anions surround each

other. Smallest piece is a FORMULA UNIT.

Two Types of Compounds

Smallest piece

Melting Point

State

Types of elements

Formula Unit Molecule

Metal and Nonmetal

Nonmetals

solidSolid, liquid or gas

High >300ºC Low <300ºC

Ionic Molecular

Chemical Formulas Shows the kind and number of atoms in

the smallest piece of a substance. Molecular formula- number and kinds of

atoms in a molecule. CO2

C6H12O6

Formula Unit The smallest whole number ratio of

atoms in an ionic compound. Ions surround each other so you

can’t say which is hooked to which.

Charges on ions For most of Group A elements,

location on the Periodic Table can tell what kind of ion they form

Elements in the same group have similar properties.

Including the charge when they are ions.

2+

1+

3+ 3- 2- 1-

Charge in groups 1A, 2A and 3A is the group number

in 5A, 6A and 7A are different.

Can also use electron dots If it has a few

it loses them

If it has many, it gains enough for octet

K+

Al3+

F -N

3-

What about the others? We have to figure those out some

other way. More on this later.

Naming ions

Cation- if the charge is always the same (Group A) just write the name of the metal.

Most transition metals can have more than one type of charge.

Indicate the charge with Roman numerals in parenthesis.

Co2+ Cobalt(II) ion

Naming ions

A few, like silver, zinc and cadmium only form one kind of ion

Don’t get roman numerals Ag+ silver ion Zn2+ zinc ion Cd2+ cadmium ion

Name theseNa1+ Sodium ionCa2+ Calcium ionAl3+ Aluminum ionFe3+ Iron(III) ionFe2+ Iron(II) ion

Li1+ Lithium ionPb2+ Lead(II) ion

Write Formulas for these

Potassium ion K1+

Magnesium ion Mg2+

Copper(II) ion Cu2+

Chromium(VI) ion Cr6+

Barium ion Ba2+

Mercury(II) ion Hg2+

Naming Anions Anions are always the same. Change the element ending to –

ide F1- Fluorine

Naming Anions Anions are always the same. Change the element ending to –

ide F1- Fluorin

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluori

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluor

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluori

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluorid

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluoride

Naming Anions Anions are always the same Change the element ending to –

ide F1- Fluoride ion

Name these

Cl1- Chloride ion N3- Nitride ion Br1- Bromide ion O2- Oxide ion Ga3+ Gallium ion

Write theseSulfide ion S2-

Iodide ion I1-

Phosphide ion P3-

Strontium ion Sr2+

Polyatomic ions Groups of atoms that stay together

and have a charge. Covalently bonded You must note these.

(pg 178 Table 2)

1- ions Acetate C2H3O2

1-

Nitrate NO31-

Nitrite NO21-

Hydroxide OH1-

Permanganate MnO41-

Cyanide CN1-

1- ions Perchlorate ClO4

1-

Chlorate ClO31-

Chlorite ClO21-

Hypochlorite1-

2- ions Sulfate SO4

2-

Sulfite SO32-

Carbonate CO32-

Chromate CrO42-

Dichromate Cr2O72-

Silicate SiO32-

3- ions Phosphate PO4

3-

Phosphite PO33-

1+ ion Ammonium NH4

1+

Adding Hydrogen to Polyatomics Hydrogen ions are 1+ Attach to other polyatomic ions-

changes charge by one Sulfate SO4

2-

Hydrogen sulfate HSO41-

Phosphate PO43-

Hydrogen phosphate HPO42-

Dihydrogen phosphate H2PO41-

Ions in Ionic Compounds

Naming Binary Ionic Compounds Binary Compounds - 2 elements. Ionic - a cation and an anion. The name is just the names of the ions. Cation first anion second Easy with Group A elements. NaCl = Na+ Cl- = sodium chloride

MgBr2 = Mg2+ Br- = magnesium bromide

Na2S

Naming Binary Ionic Compounds The problem comes with the transition

metals. Cation name includes the charge. The compound must be neutral. same number of + and – charges. Use the negative charge to find the

charge on the positive ion.

Naming Binary Ionic Compounds Write the name of CuO Need the charge of Cu O is 2- copper must be 2+ Copper(II) oxide Name CoCl3 Cl is 1- and there are three of them = 3- Co must be 3+ Cobalt(III) chloride

Naming Binary Ionic Compounds Write the name of Cu2S. Since S is 2-, the Cu2 must be 2+, so

each one is 1+. copper(I) sulfide Fe2O3 Each O is 2- 3 x 2- = 6- 2 Fe must = 6+, so each is 3+. iron(III) oxide

Naming Binary Ionic Compounds Write the names of the following KCl Na3N

CrN

Sc3P2

PbO

PbO2

Na2Se

Ternary Ionic Compounds Will have polyatomic ions At least three elements (3 capital letters) Still just name the ions

NaNO3

CaSO4

CuSO3

Ternary Ionic Compounds (NH4)2O

Fe(OH)3

LiCN

(NH4)2CO3

NiPO4

Writing Formulas The charges have to add up to zero. Get charges on pieces. Cations from name or periodic table. Anions from periodic table or polyatomic. Balance the charges by adding subscripts. Put polyatomics in parenthesis if there is

more than one of them

Writing Formulas Write the formula for calcium chloride. Calcium is Ca2+

Chloride is Cl1- Ca2+ Cl1- would have a 1+ charge. Need another Cl1- Ca2+ Cl2

1-

Crisscross Switch the numerical value of the charges

Ba2+ N3-2 3

Ba3N2 Reduce ratio if possible

Write the formulas for these Lithium sulfide tin (II) oxide tin (IV) oxide Copper (II) sulfate Iron (III) phosphide gallium nitrate Iron (III) sulfide ammonium sulfide

Write the formulas for these Ammonium chloride barium nitrate

Yes

Charge from name

Charge from table

No

Formula and

charge from

memory

Charge from table

Yes No

M+X Nm-Y

MYNmX

Ionic

Roman Numeral?

Polyatomic?

Yes

Yes

Metal

Metal (charge)

Name Name +ide

Ionic

YesNo No

Group 1A, 2A or 3A?

Poly atomic?

Things to look for If cations have (), the number is their

charge. Not how many. If anions end in -ide they are probably off

the periodic table (Monoatomic) If anion ends in -ate or -ite it is polyatomic The positive piece always gets written first Hydrogen- it depends on where it’s at

– If it is second, it’s a nonmetal -hydride

Molecular Compounds

Writing names and Formulas

Molecular compounds made of just nonmetals smallest piece is a molecule can’t be held together because of

opposite charges. can’t use charges to figure out how

many of each atom

Easier Ionic compounds use charges to

determine how many of each.

– Have to figure out charges.

– Have to figure out numbers. Molecular compounds name tells you

the number of atoms. Uses prefixes to tell you the number

Prefixes 1 mono- 2 di- 3 tri- 4 tetra- 5 penta-

6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-

Naming

Exception - we don’t write mono- if there is only one of the first element.

No ao oo double vowels when writing name, io, oi, and ai are okay.

Prefix name Prefix name -ide

To write the name write two words

Name These N2O

NO2

Cl2O7

CBr4

CO2

BaCl2

Write formulas for these diphosphorus pentoxide tetraiodine nonoxide sulfur hexaflouride nitrogen trioxide Carbon tetrahydride phosphorus trifluoride aluminum chloride diagram

Name 1 Name 2

No

Yes

Yes

NoDoes Name 2 have a prefix?

Nm Nm

PrefixPrefix

Yes

Yes

No

XxYy

Is X a metal?

Yes

Yes

No

No

Prefix+name Prefix+name+ide

(no mono)

Molecular

Acids

Writing names and Formulas

Acids Compounds that give off hydrogen ions

when dissolved in water. Must have H in them. will always be some H next to an anion. The anion determines the name.

Naming acids If the anion attached to hydrogen is

ends in -ide, put the prefix hydro- and change -ide to -ic acid

HCl - hydrogen ion and chloride ion hydrochloric acid H2S hydrogen ion and sulfide ion hydrosulfuric acid

Naming Acids If the anion has oxygen in it it ends in -ate or -ite change the suffix -ate to -ic acid HNO3 Hydrogen and nitrate ions

Nitric acid change the suffix -ite to -ous acid HNO2 Hydrogen and nitrite ions

Nitrous acid

Name these HF H3P

H2SO4

H2SO3

HCN H2CrO4

Writing Formulas Hydrogen will always be first name will tell you the anion make the charges cancel out. Starts with hydro- no oxygen, -ide no hydro, -ate comes from -ic, -ite

comes from -ous

Write formulas for these hydroiodic acid acetic acid carbonic acid phosphorous acid hydrobromic acid diagram

Name 1 Name 2

No

Yes

Is Name 2 acid?

Yes

NoDoes Name 2 have a prefix?

No

Charge from table

HYNm

Nm-Y

-ate -ite

NoYes

NoYes

Hydro- ?

-ic acid?

Yes

Yes

No

XxYy

Is X hydrogen?

Is X a metal?

Yes

Yes

No

No

Hydro____ ic acid

____ ic acid ____ ous acid

Acid

Yes

Yes

No

No

Oxygen?

-ate?

38.Name these acidsa) H2C2O4 b) HF c) HClO2 d)

H2CO3

39.Write formulas for these compoundsa) nitrous acid b) hydroselenic acidc) phosphoric acid d) acetic acid

43. Name these compoundsa) AlF3 b) SnO2 c) Fe(C2H3O2)3

d) KHSO4 e) CaH2 f) HClO3

g) Hg2Br2 h) H2CrO4

44. Write formulas for thesea) Phosphorus pentabromideb) Carbon chloridec) potassium permanganate

43. Name these compoundsa) AlF3 b) SnO2 c) Fe(C2H3O2)3

d) KHSO4 e) CaH2 f) HClO3

g) Hg2Br2 h) H2CrO4

44. Write formulas for thesea) Phosphorus pentabromideb) Carbon chloridec) potassium permanganated) Calcium hydrogen carbonatee) dichlorine heptoxidef) trisilicon tetrahydrideg) sodium dihydrogen phosphate

Summary Periodic table

– Grouped by properties Metals- make cations

– 2 types those with () and those without Nonmetals make anions

– Three types• Without O -ide• With O -ite and -ate

Only electrons can move to make ions

Summary Make all the decisions. First determine type of compound Then figure out name or formula Acid = H to start Metal = Ionic No H, No metal = molecular Only molecular get prefixes Roman numeral is NOT how many Hydro means no O