This section is about the three
types of Chemical Bonds:
But 1st lets review some facts about
atoms
and
the periodic table.
Lets review some past
facts about atoms.
1. The center of the atom is known as
the nucleus.
2. The nucleus has positive protons +
and neutral neutrons N .
3. Around the nucleus are orbits
that negative electrons - travel on.
Instead of this model
-
We will use this model
-
-
1
N
+
+
+
N
N
N N
+
1
2
2
4
F
9
9
-4
5
-
4. Now when we diagram atoms
we will summarize the subatomic
particles.
P=4
N=5
-
4 P = 4 E (0 charge)
Example: Fluorine
Now for the nucleus.
9
F
18.998 Round to one’s place
1. Fluorine is in the nonmetal section.
Row 2 Column 17.
9
F
19
9 are protons
19
-9
10 are neutrons
2. Row 2 means 2 orbits.
3. Family 17 means 7 valence
electrons.
-
N-
Nonmetals
-
NN-
N17
F
2
-
-
+ N N +
N + + N
+
N +
N +
+ N + N
N N
N-
-
P=9
N = 10
-
-
-
N-
-
4 P = 4 E (0 charge)
What is chemical bonding?
The combining of atoms of elements to form a
new substance.
Hydrogen
(a gas)
1
1
2
H
+
Oxygen
(a gas)
+
16
O
Becomes
Water molecule
Hydrogen
(a gas)
WhyHuh!
would atoms want to bond?
To stabilize their
orbits!
Meanwhile, some atoms
are trying to fill their last
orbit by gaining 3,2 or 1 e-.
These atoms
release
Some
atoms will
have
1, 2,
these
electronsin their
or
3 electrons
last
and energy
drop thelevel.
last level.
NN-
Be
+
Oxygen
P=4
N=5
N-
N-
N-
-
P=8
N=8
-
-
-
It’s all about the
valence electrons.
-
-
-
N-
metals
nonmetals
1. Forms between a metal atom and
a nonmetal atom.
2. Lets look at the metal atom Lithium
and the nonmetal atom Fluorine.
3. Atoms from the periodic table start off
neutral.
This is because the # of positive
protons = the # of negative electrons.
4. These atoms wont stay neutral for long.
-
-
5. Atoms want a full orbit, so Li & F each
have a choice.
6. For Li, will it add 7 e-’s to the last
orbit?
Li
F
-
P=3
N=4
* Notice that this would create a negative atom
-
(anion) because the electrons would out number
the protons by 7.
or
-
-
or
-
8. For F, will it gain 1 e- to the last orbit?
Li
or
9P=9E
Li
P=3
N=4
9. Will F drop the last orbit & 7 e-’s.
-
-
-
3 P = 10 E
3P=2E
-
-
-
P=9
N = 10
-
-
-
9 P = 10 E
-
or
F -
P=3
N=4
-
-
+
If you said gain 1 e-, you were correct!
-
-
-
(cation) because the protons would out number
the electrons by 1.
If you said lose e-’s, you were correct!
-
P=9
N = 10
3P=3E
7. Will Li drop the last orbit & e-.
* Notice that this would create a positive atom
-
-
-
-
F +
-
-
P=9
N=
10
-
-
-
9P=2E
-
-
Ionization energy is the energy needed to
remove electrons.
F
Li
Atoms with a few valence electrons have low
ionization energy.
-
-
-
P=3
N=4
-
P=9
N = 10
Li has low ionization energy.
-
-
Atoms with a many valence electrons have
high ionization energy.
A metal cation joining a nonmetal anion
forms a salt.
-
-
Li +
-
P=9
N = 10
-
-
-
-
F -
-
-
-
P=3
N=4
-
F has high ionization energy.
-
-
Electron affinity is the ability to attract
electrons.
Li
Atoms with a few valence electrons have low
electron affinity.
P=3
N=4
-
-
Atoms with a many valence electrons have
high electron affinity.
Li has low electron affinity.
-
-
F -
-
-
P=9
N = 10
-
-
-
F has high electron affinity.
Nonmetals
16
2
Form when a positive
metal atom……..
The metal atom will shift from
neutral to positive when it …..
* loses 1, 2 or 3 e-’s.
* Because the protons outnumber
the electrons,
* the atom to become a positive
atom (cation).
-
-
Be
The nonmetal atom will shift from
neutral to negative when it …..
* gains 1, 2 or 3 e-’s.
+
P=4
N=5
attracts to a negative
nonmetal atom.
N-
-
Oxygen P=8
N=8
-
-
-
4P>2E
-
N-
Positive and Negative Attract
-
-
8 P < 10 E
*Because the electrons outnumber
the protons,
* the atom to become a negative
atom (anion).
-
Ionic Bond, A Sea of Electrons
Nonmetals
16
2
This type of bond forms between
nonmetal atoms.
The goal is to have a full outer
level!!
Atoms joined by a covalent
bond (nonmetel to nonmetal
form a compound).
-
-
-
-
Fluorine
-
-
Fluorine
-
P=9
N = 10
P=9
N = 10
-
-
-
-
-
-
-
-
-
Fluorine
-
-
-
-
P=9
N = 10
P=9
N = 10
-
-
-
-
-
Fluorine
-
-
-
-
-
-
-
If it is two of the same element it is called diatomic.
Covalent Bonds
Slide taken from: www.education.jlab.org/.../pow
• Formed between atoms of
metallic elements
• Electron cloud around
atoms
• Good conductors at all
states, lustrous, very high
melting points
• Examples; Na, Fe, Al, Au, Co
Slide taken from: www.education.jlab.org/.../pow
Metallic Bonds: Mellow dogs with plenty
of bones to go around.
Slide taken from: www.education.jlab.org/.../pow