U4L2 - Lecture Notes - Classification of the Elements

Lesson 2 -
Classification of the Elements​

​Unit 4
The Periodic Table and Periodic Law

Essential Questions

• Why do elements in the same group have similar properties?

• Based on their electron configurations, what are the four blocks of the
periodic table?

Classification of the Elements
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Organizing the Elements by Electron Configuration

• Recall electrons in the highest principal energy level are called valence
electrons. All group 1 elements have one valence electron.

Classification of the Elements
Copyright © McGraw-Hill Education

Organizing the Elements by Electron Configuration

Classification of the Elements
Copyright © McGraw-Hill Education

• Group 2 elements have
two valence electrons.
The number of valence
electrons for elements in
groups 13–18 is ten less
than their group number.
The energy level of an
element’s valence
electrons indicates the
period on the periodic
table in which it is found.

Multiple Choice

The energy level of an element’s valence electrons indicates the ______on the periodic table in which it is found.

• Group

• Family

• Period

• Block

The s-, p-, d-, and f-Block Elements

• The shape of the periodic table becomes clear if it is divided into blocks
representing the atom’s energy sublevel being filled with valence electrons.

Classification of the Elements
Copyright © McGraw-Hill Education

Multiple Choice

What do the blocks that the periodic table is divided into represent?

• atom’s energy sublevel being filled with inner electrons

• atom’s energy sublevel being filled with valence electrons

• atom’s energy sublevel being filled with neutrons

• atom’s energy sublevel being partially filled with valence electrons

The s-, p-, d-, and f-Block Elements

• s-block elements consist of group 1 and 2, and the element helium.

• Group 1 elements have a partially filled s orbital with one electron.

• Group 2 elements have a completely filled s orbital with two electrons.

Classification of the Elements
Copyright © McGraw-Hill Education

Multiple Select

What do the s-block elements consist of ?

(Choose all that apply)

• Group 1

• Group 2

• Hydrogen

• Helium

Multiple Choice

True or False: Group 2 elements have a completely filled s orbital with two electrons.

• True

• False

The s-, p-, d-, and f-Block Elements

• Groups 13–18 fill the p orbitals. In group 18, both the s and p orbitals of the
period’s principal energy level are completely filled.

Classification of the Elements
Copyright © McGraw-Hill Education

Multiple Choice

In which group are both the s and p orbitals of the
period’s principal energy level completely filled.

• Groups 1 and 2

• Groups 13-18

• Group 18

• Transition elements

Interactive Table – Noble Gas Electron Configuration

Classification of the Elements
Copyright © McGraw-Hill Education

Go to your ConnectED resources to play Interactive Table: Noble Gas
Electron Configuration.

The s-, p-, d-, and f-Block Elements

• The d-block contains the transition metals and is the largest block.

• There are exceptions, but d-block elements usually have filled outermost s
orbitals, and filled or partially filled d orbitals.

• The five d orbitals can hold 10 electrons, so the d-block spans ten groups on
the periodic table.

Classification of the Elements
Copyright © McGraw-Hill Education

Multiple Choice

Which block contains the transition metals and is the largest block

• s

• p

• d

• f

Multiple Choice

How many electrons can the d orbitals hold?

• 10

• 5

• 2

• 8

The s-, p-, d-, and f-Block Elements

• The f-block contains the inner transition metals.

• f-block elements have filled or partially filled outermost s orbitals and filled or
partially filled 4f and 5f orbitals.

• The 7f orbitals hold 14 electrons, and the inner transition metals span 14
groups.

Classification of the Elements
Copyright © McGraw-Hill Education

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

SOLVE FOR THE UNKNOWN

•For representative elements, the
number of valence electrons can
indicate the group number.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

SOLVE FOR THE UNKNOWN

•For representative elements, the
number of valence electrons can
indicate the group number.

The s2 indicates the strontium’s valence
electrons fill the s sublevel. Thus,
strontium is in group 2 of the s-block.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

SOLVE FOR THE UNKNOWN

•For representative elements, the
number of valence electrons can
indicate the group number.

The s2 indicates the strontium’s valence
electrons fill the s sublevel. Thus,
strontium is in group 2 of the s-block.

•The number of the highest energy
level indicates the period number.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

SOLVE FOR THE UNKNOWN

•For representative elements, the
number of valence electrons can
indicate the group number.

The s2 indicates the strontium’s valence
electrons fill the s sublevel. Thus,
strontium is in group 2 of the s-block.

•The number of the highest energy
level indicates the period number.

The 5 is 5s2 indicates that strontium is in
period 5.

Classification of the Elements
Copyright © McGraw-Hill Education

Electron Configuration and the Periodic Table

EVALUATE THE ANSWER

The relationships between electron
configuration and position on the periodic
table have been correctly applied.

Use with Example Problem 1.
Problem
Strontium, which is used to produce red
fireworks, has an electron configuration of
[Kr]5s2. Without using the periodic table,
determine the group, period, and block of
strontium.

Response
ANALYZE THE PROBLEM
•You are given the electron configuration
of strontium.

KNOWN

UNKNOWN

Electron configuration = [Kr]5s2 Group = ?
Period = ?
Block = ?

SOLVE FOR THE UNKNOWN

•For representative elements, the
number of valence electrons can
indicate the group number.

The s2 indicates the strontium’s valence
electrons fill the s sublevel. Thus,
strontium is in group 2 of the s-block.

•The number of the highest energy
level indicates the period number.

The 5 is 5s2 indicates that strontium is in
period 5.