The document discusses the development and organization of the periodic table. It describes how scientists like Newlands, Meyer, and Mendeleev contributed to organizing the elements. Key features of the modern periodic table are that elements are arranged by atomic number in periods and groups. Elements have characteristic properties based on their position and electron configuration.

1. The Periodic Table and
Periodic Law
Chemistry Unit 5

2. Why does the
Periodic Table look
the way it does?

3. Main Ideas
 Periodic trends in the properties of atoms allow us to
predict physical and chemical properties.
 The periodic table evolved over time as scientists
discovered more useful ways to compare and
organize elements.
 Elements are organized into different blocks in the
periodic table according to their electron
configurations.
 Trends among elements in the periodic table include
their size and their ability to lose or attract electrons

4. Development of the
Modern Periodic Table
Objectives:
 Trace the development of the periodic
table
 Identify key features of the periodic table

5. Development of the
Periodic Table
In the 1700’s, Lavoisier compiled a list of
all the known elements of the time.
 33 elements

6. Development of the
Periodic Table
The 1800s brought large amounts of
information and scientists needed a way
to organize knowledge about elements.
 Advent of electricity – break down
compounds
 Development of the spectrometer –
identify newly isolated elements

7. Development of the
Periodic Table
The 1800s brought large amounts of
information and scientists needed a way
to organize knowledge about elements.
 Industrial revolution – new chemistry
based ingredients and compounds.
 70 known elements by 1870

8. Development of the
Periodic Table
The 1800s brought large amounts of
information and scientists needed a way
to organize knowledge about elements.
 John Newlands proposed an
arrangement where elements were
ordered by increasing atomic mass.

9. Law of Octaves
Newlands (1864)
noticed when the
elements were
arranged by
increasing atomic
mass, their
properties repeated
every eighth
element.

10. Law of Octaves
Octaves was used
due to the musical
analogy, but was
widely dismissed.
Some elements
didn’t follow the
pattern

11. The Periodic Table
 Meyer and Mendeleev both demonstrated
a connection between atomic mass and
elemental properties.

12. The Periodic Table
 Mendeleev’s Table – A Russian scientist
– gets the most credit because he
published first.
 Arranged elements by increasing mass and
columns with similar properties.
 Predicted the existence and properties of
undiscovered elements.
 Still some inconsistencies.

13. The Periodic Table
 Moseley discovered that each element
had a distinct number of protons.
 Once rearranged by increasing atomic
number, the table resulted in a clear
periodic pattern.

14. The Periodic Table
Periodic repetition of chemical and
physical properties of the elements when
they are arranged by increasing atomic
number is called periodic law.

16. The Modern Periodic
Table
 The modern periodic table contains boxes
which contain the element's name, symbol,
atomic number, and atomic mass.

17. The Modern Periodic
Table
 Rows of elements are called periods. (total of 7)
 Columns of elements are called groups. (total of
18)
 Elements in groups 1,2, and 13-18 possess a
wide variety of chemical and physical properties
and are called the representative elements.
 Elements in groups 3-12 are known as the
transition elements .

18. Types of Elements
Elements are classified as metals, non-metals, and
metalloids.
 Metals are made up of most of the representative
elements and all of the transition elements.
 They are generally shiny when smooth and clean,
solid at room temperature, and good conductors of
heat and electricity.
 Most are Ductile and Malleable –
 Ductile – the ability to be drawn into wire.
 Malleable – the ability to be pounded into sheets

19. Types of Elements
Elements are classified as metals,
non-metals, and metalloids.
 Alkali metals are all the elements in group 1,
except hydrogen, and are very reactive.
 Alkaline earth metals are in group 2, and are also
highly reactive.

20. Alkali Metals
 Alkali metals and water

21. Types of Elements
The transition elements (groups 3 - 12) are
divided into transition metals and inner
transition metals.
 The two sets of inner transition metals are
called the lanthanide series and actinide series
and are located at the bottom of the periodic
table.
 Lanthanides are phosphors – elements that
emit light when struck by electrons.

22. The Modern Periodic
Table
 Non-metals are elements that are generally
gases or brittle, dull-looking solids, and poor
conductors of heat and electricity.
 Group 17 is composed of highly reactive
elements called halogens.
 Group 18 gases are extremely unreactive and
commonly called noble gases.

23. The Modern Periodic
Table
 Metalloids have physical and chemical
properties of both metals and non-metals, such
as silicon and germanium. They are found
along the stair step of the table starting with
Boron

25. Questions
What is a row of elements on the periodic
table called?
A. octave
B. period
C. group
D. transition

26. Questions
What is silicon an example of?
A. metal
B. non-metal
C. inner transition metal
D. metalloid

27. Practice Problems
 CALM 5.1

28. Classification of the
Elements
Objectives:
 Explain why elements in the same group
have similar properties.
 Identify the four blocks of the periodic
table on their electron configuration.

29. Organizing the Elements
by Electron Configuration
Electron configuration determines the
chemical properties of an element.
 Recall electrons in the highest principal
energy level are called valence
electrons.

30. Organizing the Elements
by Electron Configuration
 All group 1 elements have one valence
electron.
 All group 2 elements have two valence
electrons.

31. Organizing the Elements
by Electron Configuration

32. Organizing the Elements
by Electron Configuration
 The energy level of an element’s valence electrons
indicates the period on the periodic table in which it
is found.
 The number of valence electrons for elements in
groups 13-18 is ten less than their group number.
 After the s-orbital is filled, valence electrons occupy
the p-orbital.

33. Organizing the Elements
by Electron Configuration

34. Organizing the Elements
by Electron Configuration

35. Organizing the Elements
by Electron Configuration
 The d-block contains the transition metals and is
the largest block.
 There are exceptions, but d-block elements usually
have filled outermost s orbital, and filled or partially
filled d orbital.
 The five d orbitals can hold 10 electrons, so the d-
block spans ten groups on the periodic table.

36. Organizing the Elements
by Electron Configuration
 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 7 f orbitals hold 14 electrons, and the inner
transition metals span 14 groups.

37. Practice Problems
 CALM 5:2

38. Periodic Trends
Objectives:
 Compare period and group trends of
several properties.
 Relate period and group trends in atomic
radii to electron configuration

39. Atomic Radius
Atomic radius – is determined by the amount of
positive charge in the nucleus and the number of
valence electrons of an atom. It is usually
measured in picometers (10-12).
 For metals, atomic radius is half the distance
between adjacent nuclei in a crystal of the
element.
 For diatomic nonmetals, the atomic radius is the
distance between nuclei of identical atoms.

40. Diatomic Nonmetals
H2, N2, O2, F2, Cl2, Br2

41. Atomic Radius

42. Organizing the Elements
by Electron Configuration

43. Atomic Radius
The periodic trend: decreases from left to right
(periods) and increases top to bottom (groups)
due to the increasing positive charge in the
nucleus.

44. Atomic Radius

45. Atomic Radius
 Atomic radius generally increases as you move
down a group.
 The outermost orbital size increases down a
group, making the atom larger.
 Valence electrons are not shielded from the
increasing nuclear charge because no additional
electrons come between the nucleus and the
valence electrons.

46. Ionic Radius
Ions – atom(s) that gain or lose one or more electrons
to form a net charge.
Ionic radius is the radius of a charged atom.
 When atoms lose electrons and form positively
charged ions, they always become smaller.
 Lost electrons are usually valence electrons and
could leave the outer orbital empty and therefore
smaller.
 Electrostatic repulsion between remaining
electrons decreases and pulls closer to nucleus.

47. Ionic Radius
 When atoms gain electrons and forms a
negatively charged ion, they become larger.
 Increased electrostatic repulsion increases
distance of outer electrons.

48. Organizing the Elements
by Electron Configuration

49. Ionic Radius
Periodic Trend: radius of an ion decreases from
left to right (periods) until charge changes and
then the radii increases dramatically. After the
change, the radius continues to decrease.
Ionic radii increases top to bottom (groups) until
change in charge.

50. Ionic Radius

51. Ionization Energy
Ionization energy is the energy needed to
remove an electron from the positive charge of
the nucleus of a gaseous atom. (how strongly
a nucleus holds on to an electron.)
 First ionization energy is the energy required to
remove the first electron.
 Removing the second electron requires more
energy, and is called the second ionization
energy.

52. Ionization Energy
 Atoms with large ionization energies have a
strong hold of its electrons and are less likely
to form positive ions.
 Atoms with low ionization energies lose their
outer electrons easily and readily form positive
ions.
 The ionization at which the large increase in
energy occurs is related to the number of
valence electrons.

53. Organizing the Elements
by Electron Configuration

54. Ionization Energy
Periodic Trend: First ionization energy increases
from left to right across a period. First ionization
energy decreases down a group because atomic
size increases and less energy is required to
remove an electron farther from the nucleus.

55. Ionization Energy
 The octet rule states that atoms tend to gain,
lose or share electrons in order to acquire a full
set of eight valence electrons. The octet rule is
useful for predicting what types of ions an
element is likely to form.

56. Ionization Energy

57. Electronegativity
Electronegativity of an element indicates
its relative ability to attract electrons in a
chemical bond. Measured in Paulings:
numbers 4 and less.

58. Electronegativity
Periodic Trend: electronegativity decreases down a
group and increases left to right across a period.

59. Questions
The lowest ionization energy is the
____.
A. first
B. second
C. third
D. fourth

60. Questions
The ionic radius of a negative ion becomes
larger when:
A. moving up a group
B. moving right to left across period
C. moving down a group
D. the ion loses electrons

61. Practice Problems
 CALM 5:3

62. Ion Formation
Objective:
 Learn the common list of cations
 Learn the common list of anions

63. Cations
 Cations are atoms or groups of
atoms that have lost electrons.

65. Anions
 Anions are atoms or groups of
atoms that have gained electrons.

67. Practice Problems
 CALM 5:4

68. 5:4 Accumulating Content
 How does the electron configuration of an atom
relate to ion formation?

69. 5:4 Accumulating Content
 How do chemical and physical properties relate
to periodic trends? What other properties might
have periodic trends?

70. 5:4 Accumulating Content
 What does a group tell us about valence
electrons and ion formation?

71. Key Concepts
 The elements were first organized by increasing
atomic mass, which led to inconsistencies. Later,
they were organized by increasing atomic
number.
 The periodic law states that when the elements
are arranged by increasing atomic number, there
is a periodic repetition of their chemical and
physical properties.
 The periodic table organizes the elements into
periods (rows) and groups (columns); elements

72. Key Concepts
 Elements are classified as either metals, nonmetals, or
metalloids.
 The periodic table has four blocks (s, p, d, f).
 Elements within a group have similar chemical properties.
 The group number for elements in groups 1 and 2 equals
the element’s number of valence electrons.
 The energy level of an atom’s valence electrons equals its
period number.

73. Key Concepts
 Atomic and ionic radii decrease from left to right
across a period, and increase as you move down a
group.
 Ionization energies generally increase from left to
right across a period, and decrease as you move
down a group.
 The octet rule states that atoms gain, lose, or share
electrons to acquire a full set of eight valence
electrons.
 Electronegativity generally increases from left to right

74. Chapter Questions
The actinide series is part of the
A. s-block elements.
B. inner transition metals.
C. non-metals.
D. alkali metals.

75. Chapter Questions
In their elemental state, which group has
a complete octet of valence electrons?
A. alkali metals
B. alkaline earth metals
C. halogens
D. noble gases

76. Chapter Questions
Which block contains the transition
metals?
A. s-block
B. p-block
C. d-block
D. f-block

77. Chapter Questions
An element with a full octet has how
many valence electrons?
A. two
B. six
C. eight
D. ten

78. Chapter Questions
How many groups of elements are
there?
A. 8
B. 16
C. 18
D. 4

79. Chapter Questions
Which group of elements are the least
reactive?
A. alkali metals
B. inner transition metals
C. halogens
D. noble gases

80. Chapter Questions
On the modern periodic table, alkaline
earth metals are found only in ____.
A. group 1
B. s-block
C. p-block
D. groups 13–18

81. Chapter Questions
Bromine is a member of the
A. noble gases.
B. inner transition metals.
C. earth metals.
D. halogens.

82. Chapter Questions
How many groups does the d-block span?
A. two
B. six
C. ten
D. fourteen

83. THE END

84. Chapter Questions

85. Chapter Questions

86. Chapter Questions

87. Chapter Questions

88. Chapter Questions