Physical Science 5.1 : Arranging the Elements


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Physical Science 5.1 : Arranging the Elements

  1. 1. The Periodic Table<br />Physical Science<br />Chapter 5<br />
  2. 2. Arranging the Elements<br />Physical Science<br />Chapter 5.1<br />
  3. 3. Objectives:<br />Describe how Mendeleev arranged elements in the first periodic table.<br />Explain how elements are arranged in the modern periodic table.<br />Comparemetals, nonmetals, and metalloids based on their properties and on their location in the periodic table.<br />Describethe difference between a period and a group.<br />
  4. 4. Discovering a Pattern<br />In 1869, Russian chemist Dmitri Mendeleev<br />Arranged the elements in order of increasing atomic mass.<br />Periodic Properties of the Elements<br />When the elements are arranged in order of increasing atomic mass<br />Those that had similar properties occurred in a repeating pattern.<br />These repeating patterns are periodic,meaning that they happen at regular intervals.<br />
  5. 5. Predicting Properties of Missing Elements<br />Mendeleev’s arrangement had gaps in its pattern.<br />Mendeleev predicted that elements yet to be found would fill these gaps.<br />He also predicted the properties of the missing elements.<br />By 1886, all of the gaps had been filled and Mendeleev’s predictions were right.<br />
  6. 6. Changing the Arrangement<br />A few elements’ properties did not fit in the pattern of Mendeleev’s table.<br />In 1914,<br />British scientist Henry Moseley found the number of protons—the atomic number—in an atom.<br />When the elements were arranged by atomic number,<br />they fit the pattern in Mendeleev’s table.<br />Periodic Law: physical and chemical properties of the elements are periodic functions of their atomic numbers.<br />
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  8. 8. Classes of Elements<br />Elements are classified as:<br />Metals<br />Nonmetals<br />Metalloids<br />The number of electrons in the outer energy level<br />One characteristic that helps determine which category an element belongs in.<br />The zigzag line on the periodic table<br />Can help you recognize which elements belong in which category.<br />
  9. 9. Metals:<br />Found to the left of the zigzag line.<br />Atoms of most metals have few electrons in their outer energy level.<br />All metals are<br />Shiny<br />Ductile<br />Malleable<br />Good conductors of electric current and thermal energy.<br />
  10. 10. Nonmetals<br />Found to the right of the zigzag line.<br />Atoms of most nonmetals have an almost complete set of electrons in their outer energy level.<br />Nonmetals are:<br />Not shiny<br />Not ductile, or malleable<br />Poor conductors of electric current and thermal energy.<br />
  11. 11. Metalloids<br />The elements that border the zigzag line.<br />Atoms of metalloids have about half of a complete set of electrons in their outer energy level.<br />have some properties of metals and some properties of nonmetals.<br />also called semiconductors<br />
  12. 12. Decoding the Periodic Table<br />Each Element is Identified by a Chemical Symbol<br />Each square on the periodic table includes<br />Element’s name<br />Chemical symbol<br />Atomic number<br />Atomic mass.<br />For most elements<br />The chemical symbol has one or two letters.<br />The newest elements have temporary three-letter symbols.<br />Atomic number<br />6<br />C12.011 Carbon<br />Chemical Symbol<br />Atomic Mass<br />Element Name<br />
  13. 13. Horizontal rows Are Called Periods<br />The chemical and physical properties of elements in a row follow a repeating pattern as you move across the period.<br />Vertical columns Are Called Groups<br />Elements in the same group often have similar chemical and physical properties.<br />Period<br />Group<br />