Warm Up
Iron can form two different
oxides ….. Fe2O3 and FeO. We
know for absolute certainty that
an oxygen anion always has a -2
charge. What is going on here
… how can there be two iron
oxides???
Warm Up-Answer
-Turns out we need to balance charges such that
compound has zero charge
-So in FeO if we have 1 oxygen atom that is always
a -2 charge then (1 O atom)(-2) = -2 …..
so then our Fe must have a +2 charge to balance
out (1 Fe atom)(+2) = +2 ….
+2 and -2 cancel out
-With Fe2O3 we have (3 O atoms)(-2) = -6
So (2 Fe)(???) = +6
The answer is of course +3 ….
Warm Up - Answer
FeO has a +2 charged iron cation
Fe2O3 has a +3 charged iron cation
Ion Formation and
Naming Ions
Chapter 7.1/9.1
Learning Objectives
• You will know what valence electrons are and how
to determine how many.
• You will be able to draw electron dot structures of
1A-8A elements
• You will understand the octet rule and how it leads
to stable cations and anions
•You will learn how to name simple anions and
cations
• You will understand how to name transition metals
and polyatomic ions
Valence Electrons
– Electrons in the highest occupied energy
level (s and p only)
– Determines chemical properties of element
– Equals the group number (A series)
– Involved in chemical bonding
Lewis Dot Structures
– Diagrams that show the valence electrons
of an atom using dots
– Also called electron dot structures
Octet Rule
– Atoms tend to gain, lose, or share
electrons until they are surrounded by
eight valence electrons
– Goal to be isoelectronic to a noble gas
Special Vocabulary
 Isoelectronic
–Ions that have the same electron
configuration
 Halide ions
–When the halogen group elements
become ions (F-, Cl-, Br-, I-)
Monoatomic Ions
 Single atom with a positive or negative
charge. Occurs when lose (cation) or gain
(anion) valence electrons
1A
Li+
Na+
K+
Rb+
Cs+
2A
3A
Be2+ B3+
Mg2+ Al3+
Ca2+
Sr2+
Ba2+
4A
5A
6A
N3- O2P3- S2As3- Se2-
7A 8A
FClBrI-
Naming Cations
 Naming of cation usually involves the name
of the element plus the word ion
Na+ would be called sodium ion
– Alternative techniques for variable charge
ions (transition elements)
Naming Transition Metal Ions
Symbol
Modern name
Cu+
Copper(I) ion
Cu2+
Copper(II) ion
Fe2+
Iron(II) ion
Fe3+
Iron(III) ion
Sn2+
Tin(II) ion
Sn4+
Tin(IV) ion
A few transition metals only have one charge and roman
numerals are not used … Ag+, Cd2+, Zn2+
Naming Anions
 Naming of anion
– Monatomic anion ends in –ide
Not chlorine … chloride
Not oxygen … oxide
Not nitrogen … nitride
– Many anions are polyatomic – need to memorize
the more common ones … chart I gave you
today.
Polyatomic Anions
Ions that are composed of more than one
atom. Most are anions (negative charge).
2SO4
sulfate
The names of most polyatomic anions
end in –ite or –ate.
Homework
Chapter 7.1 (Read!!)
page 193 (#3-9)
page 207-208 (#31,32, 62)
Chapter 9.1 (Read!!)
page 258 (#4,5,8,9)
page 281 (#42-46)