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Introduction to the Periodic Table

Introduction to the Periodic Table

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Introduction to the Periodic Table

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  1. Introduction to the Periodic Table

  2. History of the Periodic Table Empedocles and Aristotle: 5 elements 1. Earth (cold and dry) solid 2. Water (cold and wet) liquid 3. Air (hot and wet)gas 4. Fire (hot and dry) heat 5. Aetherthe divine substance that makes up heavenly spheres and heavenly bodies

  3. History (cont’d) • Lavoisier first to compile a list of known elements (33) • Berzelius developed a system of chemical symbols

  4. Dmitri Mendeleev The first periodic table was arranged by Dmitri Mendeleev in 1869 elements were arranged by increasing atomic mass and grouped according to similar properties Father of the Periodic Table

  5. Henry Moseley • In 1913, Henry Moseleyrearranged Mendeleev’s periodic table according to atomic number. He correctly determined that this is the most fundamental to chemical properties. • We still use this table!!

  6. More Definitions… Atomic number (Z): number of protons in the nucleus of the atom “fingerprint” of the atom -the identity of the atom is determined by the atomic number Atomic mass: (mass number) total number of protons and neutrons in the nucleus of the atom

  7. Key to the Periodic Table

  8. Practice

  9. Periodic Law Properties of elements tend to change in a regular pattern when elements are arranged in order of increasing atomic number

  10. The periodic table can be organized several different ways…. • periods/groups • metals/nonmetals/ metalloids • cations /anions

  11. Groups or Families A column (the things up and down) in the periodic table Elements within the same group tend to have similar properties also similar electron configurations

  12. Groups/Families Group 1: Alkali metals -very reactive, soft metals Group 2: Alkali-earth metals Groups 3-12: Transition metals -not very reactive Group 17: Halogens Group 18: Noble Gases -nonreactive

  13. Periods A row (left to right) in the periodic table Lanthanides Rare Earth Actinides Metals

  14. Metals, Nonmetals, Metalloids

  15. Metals • Element that is a good conductor of heat and electricity • at left and center of periodic table • Malleability: property of a metal by which it can be hammered or rolled into sheets • Ductile: ability of metals to be drawn into fine wire • Luster: ability of a metal to shine

  16. Nonmetals An element that is a poor conductor of heat and electricity Brittle!!! Most of these are gases are room temperature N2, O2, F2, Cl2 Hg and Br only liquids!!! Ex. Phosphorus: too reactive to exist in pure form in nature -All living things contain phosphorus!

  17. NONMETALS

  18. Metalloids An element that has some properties of metals and some characteristics of nonmetals Less malleable than metals, but less brittle than nonmetals Some have luster Semiconductors

  19. METALLOIDS

  20. Noble Gases Group 18 elements UNREACTIVE!!! Ne, Ar, Kr, Xe all used in lighting Helium (He) is used in party balloons because less dense than air

  21. Halogens Group 17 Very reactive!!! F is most reactive element