Ionic and Metallic Bonding
7.1 Ions
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
Valence Electrons
• Elements in the same group on the
periodic table seem to behave similarly.
• This is attributed to the fact that these
elements share the same number of
valence electrons.
• Valence Electrons- Electrons in the
highest occupied energy level of an
elements atom.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
Valence Electrons
• To find the number of valence electrons
in an atom of a representative element,
simply look at its group number. (except He)
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
1
Valence Electrons
• Valence electrons are usually the only
electrons used in chemical bonds.
• Typically, the valence electrons of a
particular element are represented in a Lewis
or electron dot structure.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
The Octet Rule
• Stable Noble gases are so because of
their valence electrons. They have
eight.
• The Octet Rule- In forming
compounds, atoms tend to achieve the
electron configuration of a noble gas,
which is stable. 8 electrons in their
outer shell
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
The Octet Rule
• Metallic elements (Elements on the left
side of the periodic table) tend to lose
their valence electrons.
• Atoms of some nonmetallic elements
(Elements on the right side of the
periodic table) tend to gain electrons or
to share electrons with another
nonmetallic element.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
2
Formation of Ions
• To achieve an outer shell octet elements will
manipulate their outer shell electrons.
– Cation- an atom that loses their outer shell
electrons to achieve the octet rule at a lower
energy level. Positively charged.
– Anion- an atom that gains electrons to achieve a
complete outer shell. Negatively charged.
• These Ions will always have identical
electron configurations to a noble gas.
The Nora School
Chemistry
955 Sligo Avenue
Silver Spring, Maryland 20910
Period _______
Electron Shells
2n2
n= energy level/shell
shell= 2 electron capacity
2nd shell= 8 electron capacity
3rd shell= 18 electron capacity
4th shell= 32 electron capacity
1st
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
Where do the Charges Come
From?
• Hydrogen has an AMU (Atomic Mass
Unit) value of 1. Therefore it has one
electron.
It is easier for Hydrogen to
lose an electron than to gain
one.
It now has “full shells” and is
now stable.
Now that the atom has 1
proton, 1 neutron and 0
electrons, what is this ion’s
charge?
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
3
Where do the Charges Come
From?
• Beryllium has an AMU (Atomic Mass
Unit) value of 4. Therefore it has four
It is easier for
electrons.
Beryllium to lose two
electrons than to gain
Six.
It now has “full shells”
and is now stable.
Now that the atom has
4 proton, 4 neutron
and 2 electrons, what
is this ion’s charge?
The Nora School
Chemistry
955 Sligo Avenue
Silver Spring, Maryland 20910
Period _______
Where do the Charges Come
From?
• Oxygen has an AMU (Atomic Mass
Unit) value of 8. Therefore it has eight
It is easier for Oxygen
electrons.
to gain two electrons
than to lose six.
It now has “full shells”
and is now stable.
Now that the atom has
8 proton, 8 neutron
and 10 electrons, what
is this ion’s charge?
The Nora School
Chemistry
955 Sligo Avenue
Silver Spring, Maryland 20910
Period _______
What ion and type of ion will
these atoms form?
•
•
•
•
•
•
Li
As
Cl
N
C
Mg
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
4
Halide Ions
• A special class of anions
• Anions formed from halogen atoms
• Will gain an electron to complete the
octet.
• Negative one charge.
The Nora School
955 Sligo Avenue
Silver Spring, Maryland 20910
Chemistry
Period _______
5