Chapter 5

Report
Naming Compounds
Writing 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.

1A
Representative elements
The group A
2A elements
 The tall columns

5A 7A
3A4A 6A
0
Metals
Transition metals

The Group B
elements
Dull
 Brittle
 Nonconductors
- insulators

Non-metals
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.

1F
2O
Has gained one electron
Has gained two electrons
Cations
Positive ions.
 Formed by losing electrons.
 More protons than electrons.
 Metals form cations.

1+
Has lost one electron
K
2+
Has lost two electrons
Ca
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
Types of
elements
State
Melting
Point
Ionic
Molecular
Formula Unit
Molecule
Metal and
Nonmetal
Nonmetals
solid
Solid, liquid
or gas
High >300ºC
Low <300ºC
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.
Charge in groups 1A, 2A and
3A is the group number
1+
2+ in 5A, 6A and 7A 3+ 3- 2- 1are different.
Can also use electron dots
 If
it has a few
it loses them
3+
Al
 If
it has many,
it gains
enough for
octet
3-
+
K
F
N
-
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
Na1+
2+
Ca
3+
Al
Fe3+
Fe2+
2+
Pb
1+
Li
Name these
Sodium ion
Calcium ion
Aluminum ion
Iron(III) ion
Iron(II) ion
Lead(II) ion
Lithium ion
Write Formulas for these
Potassium
ion
Magnesium
Copper(II)
ion
ion
K1+
2+
Mg
2+
Cu
6+
Cr
Chromium(VI) ion
ion
2+
Ba
Mercury(II)
2+
Hg
Barium
ion
Naming Anions
 Anions
are always the same.
 Change the element ending to – ide
1 F Fluorine
Naming Anions
 Anions
are always the same.
 Change the element ending to – ide
1 F Fluorin
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluori
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluor
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluori
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluorid
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluoride
Naming Anions
 Anions
are always the same
 Change the element ending to – ide
1 F Fluoride ion
Name these
Cl1-
N3Br1O2Ga3+
Chloride ion
Nitride ion
Bromide ion
Oxide ion
Gallium ion
Write these
Sulfide
Iodide
ion
I1-
ion
Phosphide
Strontium
S2ion P3-
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
C2H3O21-
NO311 Nitrite NO2
 Nitrate
 Hydroxide
1OH
 Permanganate
 Cyanide
CN1-
MnO41-
1- ions
 Perchlorate
ClO41-
ClO311 Chlorite ClO2
 Chlorate
1 Hypochlorite
2- ions
 Sulfate
 Sulfite
SO4
2-
SO32-
 Carbonate
 Chromate
CO322-
CrO4
 Dichromate Cr2O72 Silicate SiO32-
3- ions
3-
 Phosphate
PO4
 Phosphite
PO33-
1+ ion

Ammonium NH41+
Adding Hydrogen to Polyatomics
 Hydrogen
ions are 1+
 Attach to other polyatomic ionschanges charge by one
 Sulfate SO42 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 23 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 Cl11- would have a 1+ charge.
 Ca2+ Cl

Need another Cl1 Ca2+ Cl21
Crisscross

Switch the numerical value of the charges
33
2
2+
Ba N
Ba3 N2

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

Roman
Numeral?
Polyatomic?
Yes
No
Charge
from
name
Charge
from
table
Yes
No
Formula
and
charge
from
memory
M+X
Charge
from
table
Nm-Y
MYNmX
Ionic
Yes
Group
1A, 2A
or 3A?
Poly
atomic?
Yes
No
Yes
Metal
Name
Metal (charge)
Ionic
No
Name +ide
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

To write the name write two words
Prefix name Prefix name -ide
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.

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
Yes
No
No
Does Name 2
have a prefix?
Yes
Prefix
Prefix
Nm Nm
XxYy
Yes
No
Yes
Is X a
metal?
No
Prefix+name
(no mono)
Prefix+name+ide
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
Is Name 2
acid?
Yes
No
No
Does Name 2
have a prefix?
Yes
No
Hydro- ?
No
Yes
Charge
from
table
-ic acid?
Yes
-ate
Nm-Y
HYNm
No
-ite
XxYy
Is X
hydrogen?
Yes
No
Yes
Is X a
metal?
No
Oxygen?
Yes
-ate?
No
No
Yes
____ ic acid
____ ous acid
Acid
Hydro____ ic
acid
38.Name these acids
a) H2C2O4 b) HF
c) HClO2 d) H2CO3
39.Write formulas for these compounds
a) nitrous acid
b) hydroselenic acid
c) phosphoric acid
d) acetic acid
43. Name these compounds
a) AlF3
b) SnO2
c) Fe(C2H3O2)3
d) KHSO4
e) CaH2
f) HClO3
g) Hg2Br2
h) H2CrO4
44. Write formulas for these
a) Phosphorus pentabromide
b) Carbon chloride
c) potassium permanganate
43. Name these compounds
a) AlF3
b) SnO2
c) Fe(C2H3O2)3
d) KHSO4 e) CaH2
f) HClO3
g) Hg2Br2 h) H2CrO4
44. Write formulas for these
a) Phosphorus pentabromide
b) Carbon chloride
c) potassium permanganate
d) Calcium hydrogen carbonate
e) dichlorine heptoxide
f) trisilicon tetrahydride
g) 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

similar documents