Types of Compounds
2 Types of Compounds
Ionic
Covalent
Contrasting Ionic and Covalent
Compounds
Covalent
Ionic
Result from sharing e Result from a transfer
in e Metal & a nonmetal
2 nonmetals
Strong crystal structure Interpartical F is weak
Solid at room temp
liquid or gas
High melt pt
Low melt pt
Dissolve in water
Less soluble in water
Electrolytes Poor conductors of
electricity
I. Ionic Compoundscompounds composed of ions
1.
2.
Ionic bonds- attractive F between
ions of opp. charge
Result from a transfer of e-
Na
[Na]+
Cl
[Cl]-
A. Binary Compounds- a compound that
contains only 2 elements
To name a binary
compound
1.
2.
3.
Write the name of the + charged ion
(metal)
Add the name of the – charged ion
(nonmetal)
Change the end of the name of the
nonmetal to “ide”
Examples
NaCl
Sodium
Chlorine
ide
You try it!
Name MgO
magnesium oxide
B.
Formula- in ionic compounds,
the smallest ratio of atoms or
ions in the compound
1. formula unit – simplest ratio of ions in a
compound
Example:
How many formula units of each are
present?
2NaCl
3NaCl
NaCl
C. Predicting charges
1.
2.
3.
4.
Metals lose e-, so they form positive ions.
Nonmetals gain e-, so they form negative
ions.
Charge = oxidation #
Oxidation # is used to determine formulas.
D. Writing formulas
1.
aluminum + oxygen =
Aluminum has 3 valence, so it gives away 3 e-
Oxygen has 6 valence, so it accepts 2 e-
Al3+ +
O2- Al2O3
The oxidation numbers must add up to
zero. If not you have to multiply to make
them.
Practice Problems
E. Polyatomic ion- ion that has 2
or more different elements
1.
2.
3.
4.
A group of atoms is covalently
bonded together
The individual atoms have no
charge, but the group as a whole
does
See page 109 & handout
Quiz tomorrow on the 1st 9
polyatomic ions on the chart
5. Compounds containing
P.I.
Positive metal ions bond to negative P.I. ions
+ OH- =
NaOH
Negative nonmetal ions bond to Positive P.I.
Ex: Na+
Ex: NH4+
I- =
+
NH4I
Positive P.I. can bond with Negative P.I.
Ex: NH4+
+
OH- =
NH4OH
6. If you have to multiply P.I.,
use parentheses
Examples:
(NH4)2
Mg2+
or (H3O)3
+ NO3- =
Mg(NO3)2
7. To name compounds
containing P.I.
Name the + ion first, followed by the – ion.
Never change the name of a polyatomic
ion!!!!
Example CaCO3 = calcium carbonate
Practice Problems
Do a-d & f on Practice Problem Exercise 4.7
on pg 111 omit e & f.
F. Transition metals
1.
2.
Transition metals can have more than 1
oxidation #.
ex: Copper can be Cu+ or Cu2+
ex: Fe can be Fe2+ or Fe3+
Exceptions
a. Zn has a +2 charge
b. Ag has a +1
c. Cd has a +2
Transition metals cont.
3.
4.
A Roman numeral is put in parentheses
after the name of the transition element to
show its oxidation #.
Example:
Cu+
Cu2+
+ Cl+ Cl-
CuCl = copper(I) chloride
CuCl2 = copper(II) chloride
Practice Problems p 102
II. Molecular Substances
(covalent compounds)
Covalent bonds-form when e- are shared
1. Covalent compound- compound held
together by covalent bonds
2. Molecule- 2 or more atoms held together by
covalent bonds
B. Ionic & Covalent
Compounds can be Separated
1.
Distillation- separation method that uses
evaporation & condensation of a liquid
http://www.ktf-split.hr/glossary/en_o.php?def=distillation
C.
Molecular element- form when
atoms of the same element bond
example: O2, N2, H2, F2, Cl2
D. Allotropes-
combinations of a
single element that differ in
structure
Example: O2 is oxygen gas
O3 is ozone
E. Formulas & Names
1.
2.
3.
Write out the name of the 1st nonmetal,
followed by the 2nd nonmetal with “ide” for
an ending.
1st element is farther to the left on periodic
table.
If both are in the same group, the one
closest to the bottom goes 1st.
Formulas & Names Cont.
4.
Put a prefix on the name of each element to
show the # of atoms present.
Example: C2O = dicarbon monoxide
C3O5 = tricarbon pentoxide
5. Exceptions
a.
If only 1 atom of 1st element present, leave
off “mono”
Example: NO6 = nitrogen hexoxide
b.
If o-o or a-o appear, leave off the 1st
vowel.
F. Common Names (p182)
Some substances are known by their
common name more than their proper
name.
Examples:
1.
What is the proper name of H2O?
HCl = hydrochloric acid
H2SO4 = sulfuric acid
H3PO4 = phosphoric acid
HC2H3O2 = acetic acid
NH3 = ammonia
2. Organic compounds
a.
Hydrocarbon – compounds that contain H
and C only
Examples:
CH4 = methane
C2H6 = ethane
C3H8 = propane
C4H10 = butane
Test!!!!!!!