Introduction to the Elements_

							Introduction to the
Elements!
   Lesson Objectives:
• By the end of this lesson, you MUST be able
  to…
  • General Learning Outcome:
    • Describe ideas used in interpreting the chemical nature
      of matter, both in the past and present, and identify
      example evidence that has contributed to the
      development of these ideas

    • Specific Learning Outcome:
       − demonstrate understanding of the origins of the periodic
         table

       − distinguish between observation and theory, and provide
         examples of how models and theoretical ideas are used in
         explaining observations
What do we mean by a
chemical element?
• A chemical element is matter,
  all of whose atoms are alike in
  having the same positive charge
  on the nucleus and the same
  number of extra-nuclear
  electrons.
Where do/did the
elements come from?
• They exist in
  nature/atmosphere/universe/hu
  man body….
How do we know
anything about them?
• Greek Philosophers investigating matter

• Early alchemists

• Scientific Revolution:

  • Sir Francis Bacon

  • Robert Boyle

  • Antoine Lavoisier

  • John Dalton
Where do the names of the
chemical elements come
from?
• many sources:
 • mythological concepts or characters
 • places, areas, or countries
 • properties of the element or its
   compounds
   • Color
   • smell
   • inability to combine
 • names of scientists
 • some miscellaneous / obscure names
Assignment:

• Using the chart provided by the
  teacher, summarize the
  contributions of each to the
  development of current
  chemical element theory.

  • DUE DATE: ____________________
   How have all of these ideas
   come together to form our
   modern view of chemistry?
• Scientists have been striving for centuries
  to EXPLAIN matter!

  • Observations: how scientists gather the
    information they need to formulate theories and
    write laws

  • Theories: imaginings; creative ways to try to
    explain why something happens

  • Laws: descriptions and summaries of what has
    been observed happening
  Observations:
• Science begins with observations of nature

• Anything you see, hear, smell, taste, or touch
  is an observation

• Observations are performed by people, who
  make mistakes.

  • senses are not as fine-tuned as people like to
    believe

  • People are easily fooled - when they really want
    something to happen, they often observe it
    happening, whether it really happens or not!
How do you gain confidence
that your observation is
correct?
• tell others about it

• If other scientists can make the same
  observation, we can be more confident
  that an observation is correct

• Therefore, scientific observations must
  be repeatable.

  • Otherwise, there is no way to tell if the
    observation is correct.
How can we make our
observations repeatable?
• Formulate testable theories

• How can we do this?
  • Experimental Design
  Experimental Method:
• Make an observation

• Ask a question to guide research

• Create a hypothesis

• Test the hypothesis (with experiments)
• Make your conclusions
   • Was your hypothesis correct?
      • If so, move to theory
   • Was your hypothesis incorrect?
      • If not, start all over!

• Create a theory (based upon hypothesis – correct /
  incorrect)

• Revisit/re-design/re-formulate as necessary
       Example: The Columbus
•
       Journey
    Observation: as I look toward the horizon, it appears as if the Earth if
    round…

•   Question: Is the Earth Round?

•   Hypothesis: I predict that the Earth is round!

•   Experiment: sail around the Earth in one direction until you return to the
    same spot!

     • Conclusion: My hypothesis is correct!

•   Theory: the Earth is round! One can sail around the Earth, heading in 1
    direction, beginning at one point and returning to that same point

     • What are some other factors that could account for my conclusion?
         •   I'd better give some strength to my theory…

•   Re-testing:
     • Other captains/vessels can (and should) make the same journey to
       substantiate my conclusion) as new technology arises (satellite images,
       space travel) we can look down onto Earth and see that it is in fact
       round!
 Assignment:
• In small groups, read pages 460-463 in
  appendix of your text.

• Define all bold terms

• Clarify the difference between
  • Qualitative and quantitative observations

• Complete the Instant Practice
  Questions on page 463

  • Due date: _____________________