3. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
Monday, July 9, 2012
4. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
Monday, July 9, 2012
5. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
1.by losing electrons
Monday, July 9, 2012
6. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
1.by losing electrons
2.by gaining electrons
Monday, July 9, 2012
7. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
1.by losing electrons
2.by gaining electrons
3.by pooling electrons
Monday, July 9, 2012
8. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
1.by losing electrons
2.by gaining electrons
3.by pooling electrons
4.by sharing electrons with another element
Monday, July 9, 2012
9. Bonding
✦Atoms form bonds with other atoms using the
electrons in their outer energy levels.
✦Atoms have four ways to do form bonds.
1.by losing electrons
2.by gaining electrons
3.by pooling electrons
4.by sharing electrons with another element
✦We will be studying each of these in Section 2.
Monday, July 9, 2012
10. 1 & 2.
Gaining and Losing
Electrons
Monday, July 9, 2012
13. Sodium and Chlorine
Sodium is a soft, silvery metal.
It can react violently when added to water or to
chlorine.What makes sodium so reactive?
Monday, July 9, 2012
14. Sodium and Chlorine
Sodium is a soft, silvery metal.
It can react violently when added to water or to
chlorine.What makes sodium so reactive?
Sodium has only one electron in its outer level.
Removing this electron empties this level and leaves the
completed level below. Sodium is then stable.
Monday, July 9, 2012
15. Sodium and Chlorine
Sodium is a soft, silvery metal.
It can react violently when added to water or to
chlorine.What makes sodium so reactive?
Sodium has only one electron in its outer level.
Removing this electron empties this level and leaves the
completed level below. Sodium is then stable.
Chlorine forms bonds in a way that is the opposite
of sodium—it gains one electron. When chlorine
accepts an electron, its electron configuration becomes
stable.
Monday, July 9, 2012
18. Forming Ions
As sodium atoms lose an electron they become
more stable.
Monday, July 9, 2012
19. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
Monday, July 9, 2012
20. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
Monday, July 9, 2012
21. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
=
Monday, July 9, 2012
22. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
= 11 protons
11 electrons
(neutral)
Monday, July 9, 2012
23. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
= 11 protons
11 electrons
(neutral)
but
Monday, July 9, 2012
24. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
= 11 protons
11 electrons
(neutral)
but
after losing
one electron
Monday, July 9, 2012
25. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
= 11 protons
11 electrons
(neutral)
but
after losing 11 protons
one electron 10 electrons
(positively charged)
Monday, July 9, 2012
26. Forming Ions
As sodium atoms lose an electron they become
more stable.
But by losing an electron, the balance of electric
charges changes.
= 11 protons
11 electrons
(neutral)
but
after losing 11 protons
one electron 10 electrons
(positively charged)
Sodium becomes a positively charged ion because
there is now one fewer electron than there are
protons in the nucleus.
Monday, July 9, 2012
29. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
Monday, July 9, 2012
30. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
Monday, July 9, 2012
31. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
=
Monday, July 9, 2012
32. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
= 17 protons
17 electrons
(neutral)
Monday, July 9, 2012
33. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
= 17 protons
17 electrons
(neutral)
but
Monday, July 9, 2012
34. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
= 17 protons
17 electrons
(neutral)
after gaining
but one electron
Monday, July 9, 2012
35. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
= 17 protons
17 electrons
(neutral)
after gaining 17 protons
but one electron 18 electrons
(negatively charged)
Monday, July 9, 2012
36. Forming Ions
In contrast, chlorine becomes an ion by gaining an
electron.
= 17 protons
17 electrons
(neutral)
after gaining 17 protons
but one electron 18 electrons
(negatively charged)
It becomes negatively charged because there is one
more electron than there are protons in the nucleus.
Monday, July 9, 2012
39. Forming Ions
An atom that is no longer neutral because it has
lost or gained an electron is called an ion.
Monday, July 9, 2012
40. Forming Ions
An atom that is no longer neutral because it has
lost or gained an electron is called an ion.
Sodium ion is represented by the symbol Na+
Monday, July 9, 2012
41. Forming Ions
An atom that is no longer neutral because it has
lost or gained an electron is called an ion.
Sodium ion is represented by the symbol Na+
A chloride ion is represented by the symbol Cl-
Monday, July 9, 2012
43. Bond Formation
The positive sodium ion and the negative chloride
ion are strongly attracted to each other.
Monday, July 9, 2012
44. Bond Formation
The positive sodium ion and the negative chloride
ion are strongly attracted to each other.
This attraction, which holds the ions close
together, is a type of chemical bond called an
ionic bond.
Monday, July 9, 2012
45. Bond Formation
The positive sodium ion and the negative chloride
ion are strongly attracted to each other.
This attraction, which holds the ions close
together, is a type of chemical bond called an
ionic bond.
Monday, July 9, 2012
47. Bond Formation
Sodium and chloride ions form an ionic bond.
Monday, July 9, 2012
48. Bond Formation
Sodium and chloride ions form an ionic bond.
The compound sodium chloride, or table salt, is
formed. A compound is a pure substance
containing two or more elements that are
chemically bonded.
Monday, July 9, 2012
49. Bond Formation
Sodium and chloride ions form an ionic bond.
The compound sodium chloride, or table salt, is
formed. A compound is a pure substance
containing two or more elements that are
chemically bonded.
Monday, July 9, 2012
53. More Gains and Loses
Can elements lose or gain more than one electron?
Monday, July 9, 2012
54. More Gains and Loses
Can elements lose or gain more than one electron?
Yes!!
Monday, July 9, 2012
55. More Gains and Loses
Can elements lose or gain more than one electron?
Yes!!
Magnesium, Mg, in Group 2 has two electrons in its
outer energy level.
Magnesium can lose these two electrons and
achieve a completed energy level.
Monday, July 9, 2012
56. More Gains and Loses
Can elements lose or gain more than one electron?
Yes!!
Magnesium, Mg, in Group 2 has two electrons in its
outer energy level.
Magnesium can lose these two electrons and
achieve a completed energy level.
Oxygen, O, in Group 16 has six electrons in its outer
energy level.
Oxygen can gain two electrons and achieve a
completed energy level.
Monday, July 9, 2012
59. The two electrons, in magnesiums outer energy level, can be
gained by two chlorine atoms.
Monday, July 9, 2012
60. The two electrons, in magnesiums outer energy level, can be
gained by two chlorine atoms.
The two negatively charged chloride ions are attracted to
the positively charged magnesium ion forming ionic bonds.
Monday, July 9, 2012
61. The two electrons, in magnesiums outer energy level, can be
gained by two chlorine atoms.
The two negatively charged chloride ions are attracted to
the positively charged magnesium ion forming ionic bonds.
The compound magnesium chloride (MgCl2) is produced.
Monday, July 9, 2012
62. The two electrons, in magnesiums outer energy level, can be
gained by two chlorine atoms.
The two negatively charged chloride ions are attracted to
the positively charged magnesium ion forming ionic bonds.
The compound magnesium chloride (MgCl2) is produced.
Monday, July 9, 2012
66. Metallic Bonding - Pooling
We have just looked at how metal atoms form ionic
bonds with atoms of nonmetals.
Monday, July 9, 2012
67. Metallic Bonding - Pooling
We have just looked at how metal atoms form ionic
bonds with atoms of nonmetals.
Metals can form bonds with other metal atoms, but in
a different way.
Monday, July 9, 2012
68. Metallic Bonding - Pooling
We have just looked at how metal atoms form ionic
bonds with atoms of nonmetals.
Metals can form bonds with other metal atoms, but in
a different way.
In a metal, the electrons in the outer energy levels of
the atoms are not held tightly to individual atoms.
Instead, they move freely among all the ions in the
metal, forming a shared pool of electrons.
Monday, July 9, 2012
69. Metallic Bonding - Pooling
We have just looked at how metal atoms form ionic
bonds with atoms of nonmetals.
Metals can form bonds with other metal atoms, but in
a different way.
In a metal, the electrons in the outer energy levels of
the atoms are not held tightly to individual atoms.
Instead, they move freely among all the ions in the
metal, forming a shared pool of electrons.
Metallic bonds form when metal atoms share
their pooled electrons.
Monday, July 9, 2012
71. Metallic Bonding - Pooling
This bonding affects the properties of metals.
Monday, July 9, 2012
72. Metallic Bonding - Pooling
This bonding affects the properties of metals.
For example, when a metal is hammered into sheets or
drawn into a wire, it does not break. Instead, layers of
atoms slide over one another.
Monday, July 9, 2012
73. Metallic Bonding - Pooling
This bonding affects the properties of metals.
For example, when a metal is hammered into sheets or
drawn into a wire, it does not break. Instead, layers of
atoms slide over one another.
An ounce of gold can be
stretched into a wire 50
miles long.
Monday, July 9, 2012
74. Metallic Bonding - Pooling
This bonding affects the properties of metals.
For example, when a metal is hammered into sheets or
drawn into a wire, it does not break. Instead, layers of
atoms slide over one another.
An ounce of gold can be
stretched into a wire 50
miles long.
Monday, July 9, 2012
75. Metallic Bonding - Pooling
This bonding affects the properties of metals.
For example, when a metal is hammered into sheets or
drawn into a wire, it does not break. Instead, layers of
atoms slide over one another.
A lump of pure gold
the size of a matchbox
can be flattened into a
sheet the size of a tennis
An ounce of gold can be court.
stretched into a wire 50
miles long.
Monday, July 9, 2012
77. Metallic Bonding - Pooling
The pooled electrons tend to hold the atoms together.
Monday, July 9, 2012
78. Metallic Bonding - Pooling
The pooled electrons tend to hold the atoms together.
Metallic bonding also is the reason that metals conduct
electricity well.
Monday, July 9, 2012
79. Metallic Bonding - Pooling
The pooled electrons tend to hold the atoms together.
Metallic bonding also is the reason that metals conduct
electricity well.
The outer electrons in metal atoms readily move
from one atom to the next to transmit current.
Monday, July 9, 2012
80. Metallic Bonding - Pooling
The pooled electrons tend to hold the atoms together.
Metallic bonding also is the reason that metals conduct
electricity well.
The outer electrons in metal atoms readily move
from one atom to the next to transmit current.
Monday, July 9, 2012
85. Covalent Bonds - Sharing
Some atoms are unlikely to lose or gain electrons
because the number of electrons in their outer levels
makes this difficult.
Monday, July 9, 2012
86. Covalent Bonds - Sharing
Some atoms are unlikely to lose or gain electrons
because the number of electrons in their outer levels
makes this difficult.
Carbon has six electrons,
four of the six electrons are in
its outer energy level.
Monday, July 9, 2012
87. Covalent Bonds - Sharing
Some atoms are unlikely to lose or gain electrons
because the number of electrons in their outer levels
makes this difficult.
Carbon has six electrons,
four of the six electrons are in
its outer energy level.
Monday, July 9, 2012
88. Covalent Bonds - Sharing
Some atoms are unlikely to lose or gain electrons
because the number of electrons in their outer levels
makes this difficult.
Carbon has six electrons,
four of the six electrons are in
its outer energy level.
To obtain a more stable
structure, carbon would either
have to gain or lose four
electrons.
Monday, July 9, 2012
89. Covalent Bonds - Sharing
Some atoms are unlikely to lose or gain electrons
because the number of electrons in their outer levels
makes this difficult.
Carbon has six electrons,
This is difficult
four of the six electrons are in because gaining &
its outer energy level. losing so many
electrons takes
To obtain a more stable
structure, carbon would either
so much energy.
have to gain or lose four The alternative is
electrons. sharing electrons.
Monday, July 9, 2012
91. The Covalent Bond
The chemical bond that forms between nonmetal
atoms when they share electrons is called a
covalent bond.
Monday, July 9, 2012
92. The Covalent Bond
The chemical bond that forms between nonmetal
atoms when they share electrons is called a
covalent bond.
Shared electrons are attracted to the nuclei of both
atoms.
Monday, July 9, 2012
93. The Covalent Bond
The chemical bond that forms between nonmetal
atoms when they share electrons is called a
covalent bond.
Shared electrons are attracted to the nuclei of both
atoms.
They move back and forth between the outer energy
levels of each atom in the covalent bond.
Monday, July 9, 2012
94. The Covalent Bond
The chemical bond that forms between nonmetal
atoms when they share electrons is called a
covalent bond.
Shared electrons are attracted to the nuclei of both
atoms.
They move back and forth between the outer energy
levels of each atom in the covalent bond.
Each atom has a stable outer energy level some of the
time.
Monday, July 9, 2012
95. The Covalent Bond
The chemical bond that forms between nonmetal
atoms when they share electrons is called a
covalent bond.
Shared electrons are attracted to the nuclei of both
atoms.
They move back and forth between the outer energy
levels of each atom in the covalent bond.
Each atom has a stable outer energy level some of the
time.
Covalently bonded compounds are called molecular
compounds.
Monday, July 9, 2012
98. The Covalent Bond
The atoms in a covalent bond form a neutral particle.
Monday, July 9, 2012
99. The Covalent Bond
The atoms in a covalent bond form a neutral particle.
The neutral particle formed when atoms share electrons is
called a molecule.
Monday, July 9, 2012
100. The Covalent Bond
The atoms in a covalent bond form a neutral particle.
The neutral particle formed when atoms share electrons is
called a molecule.
Monday, July 9, 2012
101. The Covalent Bond
The atoms in a covalent bond form a neutral particle.
The neutral particle formed when atoms share electrons is
called a molecule.
No ions are involved in covalent bonding because no
electrons are gained or lost.
Ionic compounds, such as sodium chloride (NaCl), are
not referred to as molecules, because their basic units are
ions, not molecules.
Monday, July 9, 2012
104. Double and Triple Bonds
Sometimes an atom shares more than one
electron with another atom.
Monday, July 9, 2012
105. Double and Triple Bonds
Sometimes an atom shares more than one
electron with another atom.
When two pairs of electrons are involved in a
covalent bond, the bond is called a double
bond.
Monday, July 9, 2012
120. Double and Triple Bonds
Here is the sharing of three pairs of electrons
between two nitrogen atoms in the nitrogen
molecule.
Monday, July 9, 2012
121. Double and Triple Bonds
Here is the sharing of three pairs of electrons
between two nitrogen atoms in the nitrogen
molecule.
When three pairs of electrons are shared by two
atoms, the bond is called a triple bond.
Monday, July 9, 2012
122. Double and Triple Bonds
Here is the sharing of three pairs of electrons
between two nitrogen atoms in the nitrogen
molecule.
When three pairs of electrons are shared by two
atoms, the bond is called a triple bond.
Monday, July 9, 2012
126. Polar and Nonpolar Molecules
Do atoms always share their electrons equally?
Monday, July 9, 2012
127. Polar and Nonpolar Molecules
Do atoms always share their electrons equally?
The answer is no.
Monday, July 9, 2012
128. Polar and Nonpolar Molecules
Do atoms always share their electrons equally?
The answer is no.
Some atoms have a greater attraction for
electrons than others do.
Monday, July 9, 2012
129. Polar and Nonpolar Molecules
Do atoms always share their electrons equally?
The answer is no.
Some atoms have a greater attraction for
electrons than others do.
Why?????
Monday, July 9, 2012
130. Polar and Nonpolar Molecules
Do atoms always share their electrons equally?
The answer is no.
Some atoms have a greater attraction for
electrons than others do.
Why?????
Some atoms have more protons, therefore more
positive pull on the electrons.
Monday, July 9, 2012
132. Polar and Nonpolar Molecules
Chlorine attracts electrons more strongly than hydrogen
does.
Monday, July 9, 2012
133. Polar and Nonpolar Molecules
Chlorine attracts electrons more strongly than hydrogen
does.
When hydrogen and chlorine covalently bond, the shared
pair of electrons tends to spend more time near the chlorine
atom than the hydrogen atom.
Monday, July 9, 2012
134. Polar and Nonpolar Molecules
Chlorine - 17 protons Hydrogen - 1 proton
Chlorine attracts electrons more strongly than hydrogen
does.
When hydrogen and chlorine covalently bond, the shared
pair of electrons tends to spend more time near the chlorine
atom than the hydrogen atom.
Monday, July 9, 2012
135. Polar and Nonpolar Molecules
Chlorine - 17 protons Hydrogen - 1 proton
Chlorine attracts electrons more strongly than hydrogen
does.
When hydrogen and chlorine covalently bond, the shared
pair of electrons tends to spend more time near the chlorine
atom than the hydrogen atom.
Monday, July 9, 2012
137. Polar and Nonpolar Molecules
The unequal sharing makes one side of the bond more
negative than the other. Such bonds are called polar
bonds.
Monday, July 9, 2012
138. Polar and Nonpolar Molecules
The unequal sharing makes one side of the bond more
negative than the other. Such bonds are called polar
bonds.
A polar bond is a bond in which electrons are
shared unevenly.
Monday, July 9, 2012
139. Polar and Nonpolar Molecules
The unequal sharing makes one side of the bond more
negative than the other. Such bonds are called polar
bonds.
A polar bond is a bond in which electrons are
shared unevenly.
Monday, July 9, 2012
140. Water
The bonds between the oxygen atom and hydrogen
atoms in the water molecule are another example of
polar bonds.
Monday, July 9, 2012
142. “Get Away, Water!”
When water molecules are exposed to a negative
charge, the water molecules line up like magnets
with their positive ends facing the negative
charge.
They are drawn to the negative charge on the
balloon.
Water molecules also are attracted to each other.
This attraction between water molecules accounts
for many of the physical properties of water.
Monday, July 9, 2012
144. “Get Away, Water!”
Molecules that do not have these uneven charges
are called nonpolar molecules.
Monday, July 9, 2012
145. “Get Away, Water!”
Molecules that do not have these uneven charges
are called nonpolar molecules.
Because each element differs slightly in its ability
to attract electrons, the only completely nonpolar
bonds are bonds between atoms of the same
element.
Monday, July 9, 2012
146. “Get Away, Water!”
Molecules that do not have these uneven charges
are called nonpolar molecules.
Because each element differs slightly in its ability
to attract electrons, the only completely nonpolar
bonds are bonds between atoms of the same
element.
One example of a nonpolar bond is the triple bond
in the nitrogen molecule.
Monday, July 9, 2012
147. “Get Away, Water!”
Molecules that do not have these uneven charges
are called nonpolar molecules.
Because each element differs slightly in its ability
to attract electrons, the only completely nonpolar
bonds are bonds between atoms of the same
element.
One example of a nonpolar bond is the triple bond
in the nitrogen molecule.
Monday, July 9, 2012
148. Chemical Shorthand
In medieval times, alchemists were the first to
explore the world of chemistry.
They used symbols to represent elements.
Monday, July 9, 2012
149. Symbols for Atoms
Modern chemists also use symbols to represent
elements.
The symbols are universal.
Each element is represented by a one letter-, two letter-,
or three-letter symbol.
Many symbols are the first letters of the element’s name,
such as H for hydrogen and C for carbon.
Others are the first letters of the element’s name in
another language, such as K for potassium, which
stands for kalium, the Latin word for potassium.
Monday, July 9, 2012
150. Symbols for Compounds
Compounds can be described using element symbols
and numbers. The figure below shows how two
hydrogen atoms join together in a covalent bond.
The resulting hydrogen molecule is represented by the
symbol H2. The subscript 2 means that two atoms of
hydrogen are in the molecule.
Monday, July 9, 2012
152. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
Monday, July 9, 2012
153. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S
Monday, July 9, 2012
154. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S Ag2S
Monday, July 9, 2012
155. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S Ag2S NH3
Monday, July 9, 2012
156. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S Ag2S NH3
H2SO4
Monday, July 9, 2012
157. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S Ag2S NH3
H2SO4 NaOH
Monday, July 9, 2012
158. Chemical Formula
A chemical formula is a combination of chemical
symbols and numbers that shows which elements
are present in a compound and how many atoms of
each element are present.
When no subscript is shown, the number of atoms is
understood to be one.
H2S Ag2S NH3 H
H2SO4 NaOH
Monday, July 9, 2012
