Transcript PPT 6.2 Classifying the Elements
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6.2 Classifying the Elements >
Chapter 6 The Periodic Table 6.1 Organizing the Elements
6.2 Classifying the Elements
6.3 Periodic Trends Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements > CHEMISTRY & YOU
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What can you learn about each element from the periodic table?
An ID contains information specific to a particular person, such as the person ’ s name, address, height, eye color, and weight.
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6.2 Classifying the Elements >
Reading the Periodic Table
Reading the Periodic Table
What information can be displayed in a periodic table?
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6.2 Classifying the Elements >
Reading the Periodic Table The periodic table usually displays the symbols and names of the elements, along with information about the structure of their atoms.
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6.2 Classifying the Elements >
Reading the Periodic Table 5 This figure shows one square from a detailed periodic table of the elements.
• In the center is the symbol for aluminum (Al).
• The atomic number for aluminum (13) is above the symbol.
• The element name and atomic mass are below the symbol.
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6.2 Classifying the Elements >
Reading the Periodic Table This figure shows one square from a detailed periodic table of the elements.
6 • There is also a vertical column with the numbers 2, 8, and 3, which indicate the number of electrons in each occupied energy level of an aluminum atom.
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6.2 Classifying the Elements >
Reading the Periodic Table The symbol for aluminum is printed in black because aluminum is a solid at room temperature.
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6.2 Classifying the Elements >
Reading the Periodic Table • The symbols for gases are in red.
• The symbols for the two elements that are liquids at room temperature, mercury and bromine, are in blue.
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6.2 Classifying the Elements >
Reading the Periodic Table 9 The symbols for some elements are in gray. These elements are not found in nature.
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6.2 Classifying the Elements >
Reading the Periodic Table 10 The background colors in the squares are used to distinguish groups of elements in the periodic table.
• For example, two shades of orange are used for the metals in Groups 1A and 2A.
– The elements in Group 1A are called
alkali metals
.
– The elements in Group 2A are called
alkaline earth metals
.
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6.2 Classifying the Elements >
Reading the Periodic Table Some groups of nonmetals also have special names.
11 • The nonmetals of Group 7A are called
halogens
.
– The name
halogen
comes from the combination of the Greek work
hals
, meaning “ salt ” and the Latin word
genesis
, meaning “ to be born.
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6.2 Classifying the Elements >
Using Figure 6.9 in your textbook, identify the element symbol, atomic number, and atomic mass for the element silver.
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6.2 Classifying the Elements >
Using Figure 6.9 in your textbook, identify the element symbol, atomic number, and atomic mass for the element silver.
Element symbol: Ag; atomic number: 47; atomic mass: 107.87 amu
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6.2 Classifying the Elements >
Electron Configurations in Groups
Electron Configurations in Groups
How can elements be classified based on electron configurations?
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6.2 Classifying the Elements >
Electron Configurations in Groups 15 Electrons play a key role in determining the properties of elements, so there should be a connection between an element ’ s electron configuration and its location in the periodic table.
Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations.
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6.2 Classifying the Elements >
Electron Configurations in Groups
The Noble Gases
Helium, neon, and argon are examples of
noble gases
, the elements in Group 8A of the periodic table.
• These nonmetals are sometimes called the inert gases because they rarely take part in a reaction.
• The noble gases neon and argon produce the colors in this neon sign.
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6.2 Classifying the Elements >
Electron Configurations in Groups
The Noble Gases
The electron configurations for the first four noble gases in Group 8A are listed below.
17 Helium (He) Neon (Ne) Argon (Ar) Krypton (Kr) 1
s
2 1
s
2 2
s
2 2
p
6 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 2
d
10 4
s
2 4
p
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6.2 Classifying the Elements >
Electron Configurations in Groups 18
The Noble Gases
Look at the description of the highest occupied energy level for each element, which is highlighted in yellow.
• The
s
and
p
electrons sublevels are completely filled with — two electrons in the
s
sublevel and six electrons in the
p
sublevel.
Helium (He) Neon (Ne) Argon (Ar) Krypton (Kr) 1
s
2 1
s
2 2
s
2 2
p
6 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 2
d
10 4
s
2 4
p
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6.2 Classifying the Elements > CHEMISTRY & YOU
What can you learn about each element from the periodic table?
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6.2 Classifying the Elements > CHEMISTRY & YOU
What can you learn about each element from the periodic table?
You can learn an element configuration).
’ s name, its symbol, its atomic number, its atomic mass, and the number of electrons in each energy level (its electron 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements >
Electron Configurations in Groups 21
The Representative Elements
This figure shows a portion of the periodic table containing Groups 1A through 7A.
• Elements in Groups 1A through 7A are often referred to as
representative elements
because they display a wide range of physical and chemical properties.
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6.2 Classifying the Elements >
Electron Configurations in Groups
The Representative Elements
Some elements in these groups are metals, some are nonmetals, and some are metalloids.
• Most of them are solids, but a few are gases at room temperature, and one, bromine, is a liquid.
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6.2 Classifying the Elements >
Electron Configurations in Groups 23
The Representative Elements
In atoms of representative elements, the
s
and
p
sublevels of the highest occupied energy level are not filled.
• In atoms of these Group 1 A elements, there is only one electron in the highest occupied energy level.
– The electron is in an
s
sublevel.
Lithium (Li) Neon (Ne) Argon (Ar) 1
s
2 2
s
1 1
s
2 2
s
2 2
p
6 3
s
1 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 4
s
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6.2 Classifying the Elements >
Electron Configurations in Groups 24
The Representative Elements
In atoms of the Group 4A elements carbon, silicon, and germanium, there are four electrons in the highest occupied energy level.
• For any representative element, its group number equals the number of electrons in the highest occupied energy level.
Carbon (C) Silicon (Si) Argon (Ar) 1
s
2 2
s
2 2
p
2 1
s
2 2
s
2 2
p
6 3
s
2 3
p
2 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 3
d
10 4
s
2 4
p
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
In the periodic table, the B group elements separate the A groups on the left side of the table from the A groups on the right side.
• Elements in the B groups are referred to as transition elements.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
In the periodic table, the B group elements separate the A groups on the left side of the table from the A groups on the right side.
• Elements in the B groups are referred to as transition elements.
• There are two types of transition elements— transition metals and inner transition metals.
26 – They are classified based on their electron configurations.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
transition metals
are the Group B elements that are usually displayed in the main body of a periodic table.
• Copper, silver, gold, and iron are transition metals.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
transition metals
are the Group B elements that are usually displayed in the main body of a periodic table.
• Copper, silver, gold, and iron are transition metals.
• In atoms of a transition metal, the highest occupied
s
sublevel and a nearby
d
sublevel contain electrons.
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6.2 Classifying the Elements >
Electron Configurations in Groups 29
Transition Elements
The
transition metals
are the Group B elements that are usually displayed in the main body of a periodic table.
• Copper, silver, gold, and iron are transition metals.
• In atoms of a transition metal, the highest occupied
s
sublevel and a nearby
d
sublevel contain electrons.
• These elements are characterized by the presence of electrons in
d
orbitals.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
inner transition metals
are the elements that appear below the main body of the periodic table.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
inner transition metals
are the elements that appear below the main body of the periodic table.
• In atoms of these elements, the highest occupied
s
sublevel and a nearby generally contain electrons.
f
sublevel 31 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
inner transition metals
are the elements that appear below the main body of the periodic table.
• In atoms of these elements, the highest occupied
s
sublevel and a nearby generally contain electrons.
f
sublevel • The inner transition metals are characterized by the presence of electrons in
f
orbitals.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
The
inner transition metals
are the elements that appear below the main body of the periodic table.
• Uranium is an example of an inner transition metal.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Transition Elements
Before scientists knew much about inner transition metals, people referred to them as rare-earth elements.
• This name is misleading because some inner transition metals are more abundant than other elements.
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6.2 Classifying the Elements >
Electron Configurations in Groups 35
Transition Elements
Before scientists knew much about inner transition metals, people referred to them as rare-earth elements.
• This name is misleading because some inner transition metals are more abundant than other elements.
• Notice that some of the inner transition metals are not found in nature.
– These elements were prepared in laboratories using methods presented in Chapter 25.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
If you consider both the electron configurations and the positions of the elements in the periodic table, another pattern emerges.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
The periodic table is divided into sections, or blocks, that correspond to the highest occupied sublevels.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
The
s
block contains the elements in Groups 1A and 2A and the noble gas helium.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
The
p
block contains the elements in Groups 3A, 4A, 5A, 6A, 7A, and 8A, with the exception of helium.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
The transition metals belong to the
d
block, and the inner transition metals belong to the
f
block.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
Each period on the periodic table corresponds to a principal energy level.
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6.2 Classifying the Elements >
Electron Configurations in Groups
Blocks of Elements
Suppose an element is located in Period 3.
• You know that the
s
and
p
sublevels in energy levels 1 and 2 are filled with electrons.
• You then read across Period 3 from left to right to complete the configuration.
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6.2 Classifying the Elements >
Electron Configurations in Groups 43
Blocks of Elements
Suppose an element is located in Period 3.
• For transition elements, electrons are added to a
d
sublevel with a principal energy level that is one less than the period number.
• For the inner transition metals, the principal energy level of the
f
sublevel is two less than the period number.
• This procedure gives the correct electron configuration for most atoms.
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6.2 Classifying the Elements > Sample
Problem 6.1
Using Energy Sublevels to Write Electron Configurations
Use Figure 6.9 (on pages 168 and 169 in your textbook) and Figure 6.13 on page 172 in your textbook to write the electron configuration for nickel (Ni).
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6.2 Classifying the Elements > Sample
Problem 6.1
45
1 Analyze Identify the relevant concepts.
• For all elements, the atomic number is equal to the total number of electrons. • For a representative element, the highest occupied energy level is the same as the number of the period in which the element is located. • You can tell how many electrons are in this energy level from the group in which the element is located.
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6.2 Classifying the Elements > Sample
Problem 6.1
2 Calculate Apply the concepts to this problem.
Use Figure 6.9 to identify where the atom is in the periodic table and the number of electrons in the atom. Nickel is located in the fourth period and has 28 electrons.
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6.2 Classifying the Elements > Sample
Problem 6.1
47
2 Calculate Apply the concepts to this problem.
Use Figure 6.13 to determine the electron configuration.
• In nickel, the first three energy levels are full, so the configuration begins with 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 . • Next is 4
s
2 and 3
d
8 . • Put it all together: 1
s
2 2
s
2 2
p
6 3
s
2 3
p
6 3
d
8 4
s
2 .
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6.2 Classifying the Elements >
What does the period an element is located in tell you about that element
’
s electron configuration? What does the group tell you?
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6.2 Classifying the Elements >
49
What does the period an element is located in tell you about that element
’
s electron configuration? What does the group tell you?
The period tells you the highest occupied principal energy level. The group number is equal to the number of electrons in the highest occupied energy level.
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6.2 Classifying the Elements >
Key Concepts 50
The periodic table usually displays the symbols and names of elements, along with information about the structure of their atoms.
Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations.
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6.2 Classifying the Elements >
Glossary Terms 51 •
alkali metal
: any metal in Group 1A of the periodic table •
alkaline earth metal
: any metal in Group 2A of the periodic table •
halogen
: a nonmetal in Group 7A of the periodic table •
noble gas
: an element in Group 8A of the periodic table; the
s
and
p
sublevels of the highest occupied energy level are filled Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements >
Glossary Terms 52 •
representative element
: an element in an “ A ” group in the periodic table; as a group these elements display a wide range of physical and chemical properties. In their atoms, the
s
and
p
sublevels in the highest occupied energy level are partially filled •
transition metal
: one of the Group B elements in which the highest occupied
s
sublevel and a nearby contain electrons
d
sublevel generally Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements >
Glossary Terms •
inner transition metal
: an element in the lanthanide or actinide series; the highest occupied
s
sublevel and nearby
f
sublevel of its atoms generally contain electrons; also called inner transition element 53 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.
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6.2 Classifying the Elements > BIG
IDEA 54
Electrons and the Structure of Atoms
• Periodic tables may contain each element ’ s name, symbol, atomic number, atomic mass, and number of electrons in each energy level.
• The electron configuration of an element can be determined based on the location of an element in the periodic table.
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6.2 Classifying the Elements > END OF 6.2
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