Periodic table

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Periodic table

  1. 1. Periodic Table• Dmitri Mendeleev-recognized that elements had repeating patterns (periodic) and organized elements into a table by increasing atomic mass• With table he was able to predict that there would be elements still unidentified by the gaps in his table
  2. 2. • Henry Moseley - determined that the number of protons - atomic number (which is unique to each element) would allow the elements to fit into very specific pattern• All identified elements follow the periodic law – chemical and physical properties change periodically with atomic number
  3. 3. Metals• Most elements are metals• Found to the left of the zigzag line• Solid at room temp (exception: mercury and hydrogen – nonmetal)• Properties: – Shiny – Ductile – Malleable – Good conductors
  4. 4. Metalloids• Also called semiconductors• Border the zigzag line (exception Al)• Have properties of both metals and nonmetals depending on the conditions• properties: depending on conditions – Brittle – Good conductors – Some shiny (others dull)
  5. 5. nonmetals• More than half are gases at room temp• To the right of the zigzag line• Properties:• Not malleable or ductile• Not shiny or dull• Poor conductors
  6. 6. Each square on table• Each square includes:• elements name• chemical symbol (color coded to identify if element is a solid, liquid or gas at room temp)• Atomic number (protons)• Atomic mass• Background color (identifies metals, nonmetals and metalloids on table)
  7. 7. • First letter of chemical symbol is always upper case and any additional letters are lower case• Newest elements have temporary 3 letter symbols• Rows (left to right) are called periods- determines the number of energy levels• Properties gradually change moving left to right across each row from reactive (group 1) to non- reactive (group 18)
  8. 8. • Columns are called groups or family• Elements in the same group or family have similar properties moving up and down each column• Each element in a family has the same number of valence electrons in the outer shell• Group number determine the valence electrons (ex: group one – all elements in group 1 have 1 valence electron, all of the elements in group 2 have 2 valence and so on)
  9. 9. Energy Levels• 1st energy level – 2 valence electrons (max)• 2nd energy level – 8 valence electrons (max)• 3rd energy level – 8 valence electrons (max)• And so on….• Each energy level can have less valence electrons but they can not have more than the maximum valence electrons.
  10. 10. Bonds• To form bonds, elements must reach a full state of 8 valence electrons in the outermost energy level (octet rule) (Exception: would be first energy level which is full at 2-helium)
  11. 11. Group 1: Alkali metals• Metals• 1 valence electron in outer level (easily shared and form compounds easily)• Very reactive with H2O, O2 and other elements• Don’t appear in nature by themselves, only as compounds
  12. 12. Group 2 – Alkaline-Earth Metals• Metals• 2 valence electrons in outer level (slightly less reactive)
  13. 13. Group 3 – 12: Transition• Metals• 1 or 2 valence electrons in outer level (depending on element) and are less reactive
  14. 14. Lanthanides and Actinides• In periods 6 and 7 and appear at the bottom of the periodic table to keep table from being to wide• Lanthanides are shiny reactive metals• Actinides are unstable radioactive• All elements after Pu-94 (plutonium) are man-made in labs and don’t occur in nature
  15. 15. Group 13: Boron Group• Has 1 metalloid and 4 metals• 3 valence electrons in outer level and are semi reactive
  16. 16. Group 14-Carbon group• 1 nonmetal, 2 metalloids and 2 metal• 4 valence electrons in outer level and most non-reactive depending on element• Forms organic compounds (all living things contain carbon)
  17. 17. Group 15-Nitrogen Group• 2 nonmetals, 2 metalloids, 1 metal• 5 valence electrons in outer level and reactivity depends on conditions and element• P is extremely reactive and only appears in compounds
  18. 18. Group 16-Oxygen Group• 3 nonmetals, 1 metalloid, and 1 metal• 6 valence electrons in outer level and reactivity depends on element – Po-84 is radioactive
  19. 19. Group 17-Halogens• Nonmetals• 7 valence electrons in outer level and has violent reactions with alkali-metals to form salt compounds – Highly reactive with other elements – Do not appear in nature alone only in compounds
  20. 20. Group 18-Noble Gases• Nonmetals• 8 valence electrons in outer level (full level) (except helium which has 2 valence electrons, which makes helium full) and very un-reactive – inert• Do not form compounds under normal conditions
  21. 21. Hydrogen• Nonmetal• 1 electron in outer level so it is set above the alkali metals and is reactive• Properties: even though above metal category, has properties of nonmetals• Most abundant element in universe, makes up stars
  22. 22. • Atomic number = Number of Protons• Electrons equal to the number of protons• Neutrons equal atomic mass (rounded) minus the protons• Protons do not change in a atom, neutrons can change, electrons can be shared or transferred (when bonds are made)

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