1 / 15

The Periodic Table

The Periodic Table. The most important document in chemistry. Learning objectives. Define group and period as related to periodic table Describe properties of metal, semi-metal and nonmetal Write names and symbols of several common elements

lexi
Download Presentation

The Periodic Table

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Periodic Table The most important document in chemistry

  2. Learning objectives • Define group and period as related to periodic table • Describe properties of metal, semi-metal and nonmetal • Write names and symbols of several common elements • Predict type of element from position in periodic table

  3. Elements: names and symbols • All elements have a name and a symbol (one or two letters) • Symbols are used in writing compound formulae and chemical equations • It is essential to be familiar with both names and symbols for the important elements

  4. Common elements and symbols - obvious • Carbon • Calcium • Chlorine • Nitrogen • Oxygen • Aluminium • Phosphorous

  5. Common elements and symbols – less obvious • Sodium • Potassium • Iron • Mercury • Silver • Gold • Tungsten

  6. 1869Dimitri Mendeleev developed the periodic table • Ordered elements according to atomic weights and physical and chemical properties. • Only about 60 elements had been identified • Predicted existence of as-yet-undiscovered elements and their properties. Predictions often proved astonishingly accurate.

  7. The modern periodic tableThere are 92 naturally occurring elements: 2 liquids, 11 gases, 23-25 nonmetals

  8. Reduce chemistry of all elements to discussion of group behaviour • 1A ALKALI METALS: Reactive. Reactivity increases down group. Physical properties vary gradually. • 2A ALKALINE EARTH METALS : Similar to alkalis but less reactive. Lots of common calcium compounds: calcium carbonate (limestone, marble), calcium oxide (lime), calcium sulphate (gypsum, plaster of Paris)

  9. Important groups on other side of table • 7A HALOGENS: Very reactive, form lots of compounds with most elements. Chlorides in particular are common: NaCl, KCl. Reactivity decreases down group • 8A RARE, INERT, NOBLE GASES: Discovered late because of lack of compounds, all gases. Not “rare” since 1 % argon in air; He second most abundant element in universe. Very unreactive. Provide insight into properties of other elements

  10. The Periodic Table: two main types of element: metals -are shiny, lustrous; good conductors of heat and electricity. Only one metal is a liquid at room temp.

  11. The Periodic Table: non-metals - insulators (or perhaps semiconductors), poor heat conductors mostly. Solids are brittle. Several are gases, one is a liquid.

  12. The Periodic Table: semi-metals – borderline cases • Some properties are metal-like • Other properties are nonmetal-like • Semiconductors

  13. Atoms and ions • Ions are charged particles with more or less electrons than protons • Positive ion (cation) has fewer electrons • Negative ion (anion) has more electrons

  14. Ions and compounds • Ions are important in one class of compounds • Metals form positive ions • Nonmetals form negative ions • Periodic table can be used to predict charges

  15. Rules to predict ion charge • Cation • Charge = group number • Anion • Charge = - (8 - group number) • Practice with a few examples

More Related