Introduction%20to%20Atoms

1
Table of Contents

• Introduction to Atoms
• Organizing the Elements
• Metals
• Nonmetals and Metalloids
• Elements From Stardust

2
Structure of an Atom
- Introduction to Atoms

• A carbon atom consists of protons and neutrons in
  a nucleus that is surrounded by electrons.

3
Models of Atoms
- Introduction to Atoms

• For over two centuries, scientists have created
  models of atoms in an effort to understand why
  matter behaves as it does. As scientists have
  learned more, the model of the atom has changed.

4
Isotopes
- Introduction to Atoms

• Atoms of all isotopes of carbon contain six
  protons, but they differ in the number of
  neutrons. Carbon-12 is the most common isotope.

5
Previewing Visuals
- Introduction to Atoms

• Before you read, preview Figure 2. Then write two
  questions that you have about the diagram in a
  graphic organizer like the one below. As you
  read, answer your questions.

Structure of an Atom
Q. What particles are in the center of the atom?
A. Protons and neutrons
Q. What particles move around the outside of the
nucleus?
A. Electrons
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More on Atoms
- Introduction to Atoms

• Click the PHSchool.com button for an activity
  about atoms.

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End of SectionIntroduction to Atoms
8
Finding Data on Elements
- Organizing the Elements

• Each square of the periodic table includes an
  elements atomic number, chemical symbol, name,
  and atomic mass.

9
Periodic Table Activity
- Organizing the Elements

• Click the Active Art button to open a browser
  window and access Active Art about the periodic
  table.

10
Organization of the Periodic Table
- Organizing the Elements

• The 18 columns of the periodic table reflect a
  repeating pattern of properties that generally
  occur across a period.

11
Asking Questions
- Organizing the Elements

• Before you read, preview the red headings. In a
  graphic organizer like the one below, ask a what
  or how question for each heading. As you read,
  write answers to your questions.

Question
Answers
What pattern of elements did Mendeleev discover?
Patterns appeared when the elements were arranged
in order of increasing atomic mass.
Atomic number, chemical symbols and names, and
average atomic mass
What data about elements is found in the periodic
table?
How are elements organized in the periodic table?
Elements are organized in periods and groups
based on their properties.
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End of SectionOrganizing the Elements
13
Metals in the Periodic Table
- Metals

• The metals in Group 1, from lithium to francium,
  are called the alkali metals. Alkali metals react
  with atoms of other elements by losing one
  electron.

14
Metals in the Periodic Table
- Metals

• Group 2 of the periodic table contains the
  alkaline earth metals. These elements are not as
  reactive as the metals in Group 1, but they are
  more reactive than most other metals.

15
Melting Points in a Group of Elements
- Metals

• The properties of elements within a single group
  in the periodic table often vary in a certain
  pattern. The following graph shows the melting
  points of Group 1 elements (alkali metals) from
  lithium to francium.

16
Melting Points in a Group of Elements
- Metals

• Reading Graphs
• As you look at Group 1 from lithium to francium,
  describe how the melting points of the alkali
  metals change.

• Melting points decrease from lithium to francium.

17
Melting Points in a Group of Elements
- Metals

• Predicting
• If element number 119 were synthesized, it would
  fall below francium in Group 1 of the periodic
  table. Predict the approximate melting point of
  new element 119.

• New element 119 should have a melting point of
  approximately 25ºC.

18
Melting Points in a Group of Elements
- Metals

• Interpreting Data
• Room temperature is usually about 22ºC. Human
  body temperature is 27ºC. Which of the alkali
  metals are liquids at room temperature? Which
  might melt if you could hold them in your hand?

• None of the alkali metals are liquids at room
  temperature. Cesium and francium might melt if
  you could hold them in your hand.

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Metals in the Periodic Table
- Metals

• The transition metals are less reactive than the
  metals in Groups 1 and 2.

20
Metals in the Periodic Table
- Metals

• Only some of the elements in Groups 13 through 15
  of the periodic table are metals. These metals
  are not nearly as reactive as those on the left
  side of the table.

21
Metals in the Periodic Table
- Metals

• Lanthanides are soft, malleable, shiny metals
  with high conductivity.

22
Metals in the Periodic Table
- Metals

• The elements below the lanthanides are called
  actinides. Many of these elements are so unstable
  that they last for only a fraction of a second
  after they are made.

23
Using Prior Knowledge
- Metals

• Before you read, write what you know about metals
  in a graphic organizer like the one below. As you
  read, write what you learn.

What You Know

1. Metals are shiny.
2. Some metals are magnetic.

What You Learned

1. Ductile metals can be pulled into a wire.
2. Alkali metals react by losing one electron.

24
Links on Metals
- Metals

• Click the SciLinks button for links on metals.

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End of SectionMetals
26
Properties of Nonmetals
- Nonmetals and Metalloids

• When nonmetals react with metals, one or more
  electrons move from the metal atoms to the
  nonmetal atoms.

27
Families of Nonmetals
- Nonmetals and Metalloids

• Each element in the carbon family has atoms that
  can gain, lose, or share four electrons when
  reacting with atoms of other elements.

28
Families of Nonmetals
- Nonmetals and Metalloids

• Group 15, the nitrogen family, contains two
  nonmetals nitrogen and phosphorus. These
  non-metals usually gain or share three electrons
  when reacting with atoms of other elements.

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Families of Nonmetals
- Nonmetals and Metalloids

• Group 16, the oxygen family, contains three
  nonmetals oxygen, sulfur, and selenium. These
  elements usually gain or share two electrons when
  reacting with atoms of other elements.

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Families of Nonmetals
- Nonmetals and Metalloids

• The Group 17 elements are the most reactive
  nonmetals. Atoms of these elements easily form
  compounds by sharing or gaining one electron when
  reacting with atoms of other elements.

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Families of Nonmetals
- Nonmetals and Metalloids

• The elements in Group 18 are known as the noble
  gases. They do not ordinarily form compounds
  because atoms of noble gases do not usually gain,
  lose, or share electrons.

32
Families of Nonmetals
- Nonmetals and Metalloids

• Because the chemical properties of hydrogen
  differ very much from those of the other
  elements, it really cannot be grouped into a
  family.

33
The Metalloids
- Nonmetals and Metalloids

• The metalloids have some characteristics of both
  metals and nonmetals. The most useful property of
  the metalloids is their varying ability to
  conduct electricity.

34
Using Prior Knowledge
- Nonmetals and Metalloids

• Before you read, write what you know about
  nonmetals in a graphic organizer like the one
  below. As you read, write what you learn.

What You Know

1. Nonmetals are not shiny.
2. Nonmetals are not magnetic.

What You Learned

1. Nonmetals are dull and brittle.
2. Metalloids have characteristics of metals and
   nonmetals.

35
Links on Nonmetals
- Nonmetals and Metalloids

• Click the SciLinks button for links on nonmetals.

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End of SectionNonmetals and Metalloids
37
How Elements Form in Stars
- Elements From Stardust

• Nuclear fusion, which occurs in stars on a huge
  scale, combines smaller nuclei into larger
  nuclei, creating heavier elements.

38
Sequencing
- Elements From Stardust

• As you read, make a flowchart like the one below
  that shows how elements are formed in stars.
  Write the steps in separate boxes in the
  flowchart in the order in which they occur.

Hydrogen nuclei fuse, forming helium.
Helium nuclei fuse, forming beryllium.
Fusion continues in smaller stars, forming
elements up to oxygen.
Fusion in larger stars produces heavier elements
up to iron.
The heaviest elements form during supernova
explosions of the most massive stars.
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Links on Nuclear Fusion
- Elements From Stardust

• Click the SciLinks button for links on nuclear
  fusion.

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End of SectionElements From Stardust
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Graphic Organizer

Periodic table
is made up of
organizes
Elements
Rows
Columns
called
called
in order of increasing
Atomic number
Periods
Families
or
and shows
Patterns of properties
Groups
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End of SectionGraphic Organizer