Classification Of Elements

9,805 views

Published on

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
9,805
On SlideShare
0
From Embeds
0
Number of Embeds
39
Actions
Shares
0
Downloads
135
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Classification Of Elements

  1. 1. Classification of Elements January 15, 2010
  2. 2. Objectives <ul><li>Describe characteristics of metals, nonmetals, and metalloids </li></ul><ul><li>Define period, periodic law, family, malleable, ductile. valence electrons </li></ul><ul><li>Describe how elements are arranged on the periodic table </li></ul>
  3. 4. Henry Mosley (1914) <ul><li>Determined that each atom has a unique number of positive charges. </li></ul><ul><li>Discovered isotopes </li></ul><ul><li>Rearranged Mendeleyev’s table by their atomic number </li></ul>
  4. 6. Periodic Law <ul><li>Because properties of elements repeated in an orderly way, it was called periodic . </li></ul><ul><li>Properties of elements are a function of their atomic numbers.  </li></ul>
  5. 7. Metals <ul><li>shiny (they have luster) </li></ul><ul><li>solids at room temperature </li></ul><ul><li>good conductors </li></ul><ul><li>malleable - capable of being hammered out into thin sheets </li></ul><ul><li>ductile - drawn out into wire or threads </li></ul>
  6. 8. <ul><li>Located to the left of the zigzag line </li></ul><ul><li>Most elements are metals </li></ul><ul><li>Usually have few valence electrons </li></ul>
  7. 9. Non-metals <ul><li>Can be found as solids, liquids, or gases at room temperature </li></ul><ul><li>Typically dull and brittle </li></ul><ul><li>Poor conductors </li></ul><ul><li>All non-metals except hydrogen are found on the right side of the zigzag line </li></ul><ul><li>Many valance electrons </li></ul>
  8. 10. Metalloids <ul><li>Border both sides of the zigzag line </li></ul><ul><li>each has some of the properties of a metal and non metal </li></ul><ul><li>can become good conductors under certain conditions such as high temperatures </li></ul><ul><li>Also called semiconductors </li></ul>
  9. 11. Elements are arranged: Vertically into Groups or Families Horizontally Into Periods
  10. 12. Every element in a family has the same number of valence electrons
  11. 13. Definition of Valence Electrons <ul><li>Valence electrons </li></ul><ul><ul><li>Number of electrons an element has in its outermost orbital </li></ul></ul><ul><ul><li>Periodic Table shows this by classifying the elements in families that all have the same number of valence electrons </li></ul></ul><ul><ul><li>Group number tells how many valence electrons each element in that family will have </li></ul></ul>
  12. 14. The group 2 atoms all have 2 electrons in their outer shells Be (Beryllium) Atom Mg (Magnesium) Atom
  13. 15. If you looked at an atom from each element in a period Each atom has the same number of electron shells .
  14. 16. The period 4 atoms each have 4 electron containing shells K (Potassium) Atom Fe (Iron) Atom Kr (Krypton) Atom 4 th Shell

×