Transcript Chapter 5
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-
N3Br1O2Ga3+
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