The Periodic Table

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The Periodic Table
Chapter 12
Preview
Section 1 Arranging the Elements Section 2
Grouping the Elements
Concept Mapping
2
Section 1 Arranging the Elements
Chapter 12
Bellringer
Think of all the ways a deck of cards could be
laid out so that the cards form some sort of
identifiable pattern. Write down as many
patterns as you can in your science journal.
3
Section 1 Arranging the Elements
Chapter 12
Objectives

• Describe how Mendeleev arranged elements in the
  first periodic table.
• Explain how elements are arranged in the modern
  periodic table.
• Compare metals, nonmetals, and metalloids based
  on their properties and on their location in the
  periodic table.
• Describe the difference between a period
• and a group.

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Section 1 Arranging the Elements
Chapter 12
Discovering a Pattern

• In 1869, Russian chemist Dmitri Mendeleev
  arranged the elements in order of increasing
  atomic mass.
• Periodic Properties of the Elements When the
  elements are arranged in order of increasing
  atomic mass, those that had similar properties
  occurred in a repeating pattern.
• These repeating patterns are periodic, meaning
  that they happen at regular intervals.

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Section 1 Arranging the Elements
Chapter 12
Discovering a Pattern, continued

• Predicting Properties of Missing Elements
  Mendeleevs arrangement had gaps in its pattern.
  Mendeleev predicted that elements yet to be found
  would fill these gaps. He also predicted the
  properties of the missing elements.
• By 1886, all of the gaps had been filled and
  Mendeleevs predictions were right.

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Section 1 Arranging the Elements
Chapter 12
Changing the Arrangement

• A few elements properties did not fit in the
  pattern of Mendeleevs table.
• In 1914, British scientist Henry Moseley found
  the number of protonsthe atomic numberin an
  atom.
• When the elements were arranged by atomic
  number, they fit the pattern in Mendeleevs table.

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Section 1 Arranging the Elements
Chapter 12
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Section 1 Arranging the Elements
Chapter 12
The Periodic Table and Classes of Elements

• Elements are classified as metals, nonmetals,
  and metalloids, according to their properties.
• The number of electrons in the outer energy
  level of an atom is one characteristic that helps
  determine which category an element belongs in.
• The zigzag line on the periodic table can help
  you recognize which elements belong in which
  category.

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Section 1 Arranging the Elements
Chapter 12
The Periodic Table and Classes of Elements,
continued

• Metals are found to the left of the zigzag line.
  Atoms of most metals have few electrons in their
  outer energy level.
• Most metals are shiny, ductile, malleable, and
  are good conductors of electric current and
  thermal energy.

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Section 1 Arranging the Elements
Chapter 12
The Periodic Table and Classes of Elements,
continued

• Nonmetals are found to the right of the zigzag
  line. Atoms of most nonmetals have an almost
  complete set of electrons in their outer energy
  level.
• Nonmetals are not shiny, ductile, or malleable,
  and are poor conductors of electric current and
  thermal energy.

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Section 1 Arranging the Elements
Chapter 12
The Periodic Table and Classes of Elements,
continued

• Metalloids are the elements that border the
  zigzag line. Atoms of metalloids have about half
  of a complete set of electrons in their outer
  energy level.
• Metalloids have some properties of metals and
  some properties of nonmetals.
• Metalloids are also called semiconductors.

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Section 1 Arranging the Elements
Chapter 12
Decoding the Periodic Table

• Each Element is Identified by a Chemical Symbol
  Each square on the periodic table includes an
  elements name, chemical symbol, atomic number,
  and atomic mass.
• For most elements, the chemical symbol has one
  or two letters. The newest elements have
  temporary three-letter symbols.

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Section 1 Arranging the Elements
Chapter 12
Decoding the Periodic Table, continued

• Rows Are Called Periods Each horizontal row of
  elements is called a period. The chemical and
  physical properties of elements in a row follow a
  repeating pattern as you move across the period.
• Columns Are Called Groups Each vertical column
  of elements is called a group. Elements in the
  same group often have similar chemical and
  physical properties.

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Section 2 Grouping the Elements
Chapter 12
Bellringer
How do you know that a bird is a bird, that a
kangaroo is a kangaroo, and that a shark is a
shark? What characteristics of each animal help
you to tell the animals apart? How can such an
analysis of characteristics be applied to
elements?
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Section 2 Grouping the Elements
Chapter 12
Objectives

• Explain why elements in a group often have
  similar properties.
• Describe the properties of the elements in the
  groups of the periodic table.

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Section 2 Grouping the Elements
Chapter 12
Group 1 Alkali Metals

• Alkali metals are elements in Group 1 of the
  periodic table. Alkali metal properties
• group contains metals
• 1 electron in the outer level
• very reactive
• softness, color of silver, shininess, low density

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Section 2 Grouping the Elements
Chapter 12
Group 2 Alkaline-Earth Metals

• Alkaline-earth metals are elements in Group 2.
  Alkaline-earth metal properties
• group contains metals
• 2 electrons in the outer level
• very reactive, but less reactive than alkali
  metals
• color of silver, higher densities than alkali
  metals

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Section 2 Grouping the Elements
Chapter 12
Group 312 Transition Metals

• Transition metals are in Groups 312. Some of
  the transition metals are shown below.

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Section 2 Grouping the Elements
Chapter 12
Group 312 Transition Metals, continued

• Properties of Transition Metals vary widely but
  include
• groups contains metals
• 1 or 2 electrons in the outer level
• less reactive than alkaline-earth metals
• shininess, good conductors of electric current
  and thermal energy

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Section 2 Grouping the Elements
Chapter 12
Group 312 Transition Metals, continued

• Lanthanides and Actinides Some transition
  metals from Periods 6 and 7 appear in two rows at
  the bottom of the periodic table. Elements in the
  first row are called lanthanides and elements in
  the second row are called actinides.

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Section 2 Grouping the Elements
Chapter 12
Group 13 Boron Group

• Aluminum is the most common element from Group
  13. Group 13 properties
• group contains one metalloid and five metals
• 3 electrons in the outer level
• reactive
• solids at room temperature

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Section 2 Grouping the Elements
Chapter 12
Group 14 Carbon Group

• Group 14 properties
• group contains one nonmetal, two metalloids, and
  two metals
• 4 electrons in the outer level
• reactivity varies among the elements
• solids at room temperature

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Section 2 Grouping the Elements
Chapter 12
Group 15 Nitrogen Group

• Group 15 properties
• group contains two nonmetals, two metalloids,
  and two metals
• 5 electrons in the outer level
• reactivity varies among the elements
• solids at room temperature (except for nitrogen,
  which is a gas)

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Section 2 Grouping the Elements
Chapter 12
Group 16 Oxygen Group

• Group 16 properties
• group contains three nonmetals, one metalloids,
  and one metal
• 6 electrons in the outer level
• reactive
• solids at room temperature (except for oxygen,
  which is a gas)

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Section 2 Grouping the Elements
Chapter 12
Group 17 Halogens

• Halogens are the elements in Group 17. Group 17
  properties
• group contains nonmetals
• 7 electrons in the outer level
• very reactive
• poor conductors of electric current, never in
  uncombined form in nature

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Section 2 Grouping the Elements
Chapter 12
Group 18 Noble Gases

• Noble gases are the elements in Group 18. Group
  18 properties
• group contains nonmetals
• 8 electrons in the outer level (except helium,
  which has 2)
• unreactive
• colorless, odorless gases at room temperature

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Section 2 Grouping the Elements
Chapter 12
Hydrogen

• The properties of hydrogen do not match the
  properties of any single group, so hydrogen is
  set apart.
• a nonmetal
• 1 electron in the outer level
• reactive
• colorless, odorless gas at room temperature, low
  density

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Section 2 Grouping the Elements
Chapter 12
Periodic Table Overview
Click below to watch the Visual Concept.
Visual Concept
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The Periodic Tables
Chapter 12
Concept Mapping
Use the terms below to complete the Concept
Mapping on the next slide.
elements periods metals electrons nonmetals periodic table groups (families)

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The Periodic Table
Chapter 12
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The Periodic Table
Chapter 12