Ionic Compounds and Metals
Section 7.1 Ion Formation
Section 7.2 Ionic Bonds and Ionic
Compounds
Section 7.3 Names and Formulas
for Ionic Compounds
Section 7.4 Metallic Bonds and the
Properties of Metals
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Section 7.1 Ion Formation
• Define a chemical bond.
• Describe the formation of
positive and negative ions.
• Relate ion formation to
electron configuration.
octet rule: atoms tend to
gain, lose, or share
electrons in order to acquire
eight valence electrons
chemical bond
cation
anion
Ions are formed when atoms gain or
lose valence electrons to achieve a
stable octet electron configuration.
Valence Electrons and Chemical Bonds
• A chemical bond is the force that holds
two atoms together.
• Chemical bonds form by the attraction
between the positive nucleus of one atom
and the negative electrons of another atom.
• They can also form by the attraction between
positive and negative ions.
Valence electrons are the outer shell electrons
of an atom. The valence electrons are the
electrons that participate in chemical bonding.
Group
1
2
13
14
15
16
17
e- configuration # of valence ens1
1
ns2
2
ns2np1
ns2np2
3
4
ns2np3
5
ns2np4
6
ns2np5
7
Valence Electrons and Chemical Bonds (cont.)
• Atom’s try to form an octet — the stable
arrangement of eight valence electrons in
the outer energy level— by gaining or
losing valence electrons.
• Noble gases are unreactive because
they have a filled valence shell.
– If sodium (element 11) were to lose one
valence electron, its electron configuration
would be like neon.
– They would both have 10 electrons
– The number of protons, however, would still
be different.
• Na = 11 protons
• Ne = 10 protons
• Elements want to obtain the same
number of electrons as the closest
Noble Gas
• SO…
– Metals and Hydrogen tend to lose electrons to
achieve the same number of electrons as a
noble gas (POSITIVE IONS + = CATIONS)
– Nonmetals tend to gain electrons to achieve
the same number of electrons as a noble gas
(NEGATIVE IONS = ANIONS)
Positive Ion Formation
*Positive ions form when an
atom loses one or more
valence electrons.
• A positively charged ion is
called a cation.
• The number of Protons
does not change
Positive Ion Formation (cont.)
• Metals are reactive because they lose
valence electrons easily.
Positive Ion Formation (cont.)
• Transition metals commonly form 2+ or 3+
ions, but can form greater than 3+ ions.
• Other relatively stable electron arrangements
are referred to as pseudo-noble gas
configurations.
Negative Ion Formation
•Negative ions form when
an atom gains one or
more valence electrons.
• An anion is a negatively
charged ion.
•The number of Protons
does not change
Negative Ion Formation (cont.)
• Nonmetal ions gain the number of
electrons required to fill an octet.
• Some nonmetals can gain or lose electrons to
complete an octet.
• Group 1 elements = +1 ions
• Group 2 elements = +2 ions
• Groups 3-12 elements = more than one
charge (all positive) typically +2,+3,+4
• Group 13 elements = +3 ions (B, Al, Ga, In
and Tl)
• Group 14 elements can be +4, -4, or 0. C
and Si usually 0, Ge, Sn, and Pb +2 or +4
• Group 15 elements of N, P, and As are
-3 ions, Sb and Bi are usually (+ ions)
• Group 16 elements of O, S, Se, Te are
-2 ions
• Group 17 elements = -1 ions all of them
• Group 18 element = 0 charge = Noble
gases (not reactive)
• For each ion, give the number of protons,
electrons and what group they belong to.
• Se-2
protons
electrons
group
• Sr+2
protons
electrons
group
Section 7.1 Assessment
Oxygen gains two electrons to form what
kind of ion?
A. 1– anion
B. 2– anion
D
A
0%
C
D. 2+ cation
A. A
B. B
C. C
0%
0%
0%
D. D
B
C. 1+ cation
Section 7.1 Assessment
Elements with a full octet have which
configuration?
A. ionic configuration
B. halogen configuration
D
A
0%
C
D. transition metal configuration
A. A
B. B
C. C
0%
0%
0%
D. D
B
C. noble gas configuration