Bell Ringer9-28-09

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Bell Ringer 9-28-09

1. What two other things does the atomic number tell
   you?
2. Where can the atomic number be found in the
   element square?
3. Where can the atomic mass be found in the element
   square?
4. Atomic mass rounded is called __________.
5. How do we find the number of neutrons in an atom?

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Objectives

• ALCOS 2
• Describe the structure of atoms.
• ALCOS 3
• Determine the of protons, neutrons, and
  electrons of atoms.

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Chapter 4 Section 2Organizing the Elements
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Mendeleev

• In 1869, he created the first periodic table.
• He noticed a pattern in the elements when he
  arranged them in order of increasing atomic mass.

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Henry Moseley

• Rearranged the Periodic Table in order of
  increasing atomic number instead of mass

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Periodic Tables Organization

• The properties of an element can be predicted
  from its location in the periodic table.
• Today, the periodic table is arranged in order of
  increasing atomic number.

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Organization of the Periodic Table

• Periods- the horizontal rows (sideways)
• There are 7 periods.
• Groups (Families)- the vertical columns
  (up-and-down)
• There are 18 groups.

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Element Square
1 H Hydrogen 1.0079
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Elements

• 1-92 ? Found in nature
• All elements above 92 ? synthetic (man-made)

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Elements in the Human Body

• Oxygen (65)
• Carbon (18)
• Hydrogen (10)
• Nitrogen (3)
• Calcium (1.5)
• Phosphorus (1.0)
• Potassium (0.35)
• Sulfur (0.25)
• Sodium (0.15)
• Magnesium (0.05)
• Copper, Zinc, Selenium, Molybdenum, Fluorine,
  Chlorine, Iodine, Manganese, Cobalt, Iron (0.70)
  
• Lithium, Strontium, Aluminum, Silicon, Lead,
  Vanadium, Arsenic, Bromine (trace amounts)

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Sun

• The sun is mostly made of Hydrogen.
• It exists at very high temperatures (15 million
  degrees Celsius).
• At these high temps, matter cannot exist as a
  solid, liquid, or gas, so it is plasma.

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Stars

• Nuclear Fusion- when 2 atomic nuclei combine,
  forming a larger nucleus (releases a lot of
  energy)
• Happens in stars

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Stars

• Nuclear Fusion

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Interactive Websites

• Periodic Table of the Elements
• The Periodic Table of the Elements, Standard Form