This presentation is on the Periodic Table.ppt
- 1. 1
- 2. Periodic Table Periods and Groups Block of elements Periodicity of Properties Trends in periodic table Transition metals Oxidation /Reduction reactions
- 3. Quote
- 4. Learning The Periodic Table of Elements
- 6. How is it Arranged? • The elements are put into rows by increasing ATOMIC NUMBER. • The horizontal rows are called periods and are labeled 1 to 7. • The vertical rows are called groups and are labeled 1 to 18 The red lines show the different periods and the green lines show the groups.
- 7. Grouped Elements Have Similarities • Elements in the same group have similar properties. Remember, groups are columns. • Chemical Property - a property used to characterize materials in reactions that change their identity. Ex: burning something. • Physical Property - a characteristic of a substance that can be observed without changing the substance into something else. Ex: measuring something’s length, color, mass or volume.
- 9. Metals, Nonmetals and Metalloids • The major categories of elements are the metals, non-metals, and metalloids. • Metals are lustrous, malleable, and are good conductors of heat and electricity. • Non-metals are elements that do not share the properties of metals. • Metalloids are elements that share some, but not all the properties of metals.
- 10. Metals - Lustrous, Malleable, and Good Conductors? These are physical properties of metals • Lustrous means shiny or reflective of light. – Coins and jewelry are shiny and reflective . • Malleable means capable of being shaped. – Aluminum foil is shaped or molded around food items to keep them fresh. • Being a Good Conductor means being able to allow electricity and heat to flow through. − When you think about the wires we use for electrical devices, they are mostly made of copper and other metals.
- 11. Alkali Metals • Elements in Group 1 (not including Hydrogen). • Very reactive metals. Always combine with something else in nature. • Salt – an Alkali Metal, Sodium, and another element, Chlorine, combined.
- 12. Alkaline Earth Metals • Elements in Group 2. • Reactive Metals that are always combined with non-metals in nature. • Several of these elements are important mineral nutrients, like Calcium.
- 13. Transition Metals • Elements in Groups 3-12. • Less reactive, harder metals. • Includes metals used in jewelry, money and construction.
- 14. Boron Family • Elements in Group 13. • Boron has properties of both metals and non-metals. • The rest of the elements in this group are metals.
- 15. Carbon Family • Elements in Group 14. • Contains elements important to life and computers. • Carbon is the basic element in all organic compounds. • Silicon and Germanium are important semiconductors.
- 16. Nitrogen Family • Elements in Group 15. • Nitrogen makes up more than ¾ of our atmosphere. • The red tip of matches is made of phosphorous.
- 17. Oxygen Family or Chalcogens • Elements in Group 16. • Oxygen is necessary for respiration. • Many things that have a bad odor contain sulfur.
- 18. Halogens • Elements in Group 17. • Very reactive, diatomic non-metals. • Always found combined with other elements in nature. • Chlorine is used to keep bacteria out of swimming pools.
- 19. Noble Gases • Elements in Group 18. • VERY reactive gases. • Used in lighted neon signs. • Helium is used to make party balloons float.
- 20. Elements Used Everyday Can you think of any elements you use every day?
- 21. The Periodic Table of Elements •Elements are organized according to their physical and chemical properties in the Periodic Table of the Elements. Historically, several people contributed to this effort in the late 19th century: –Dobereiner- “triads”: Ca, Sr, Ba; Li, Na, K –Newlands- similarity between every eighth element –Mendeleev (1870) - Arranged elements according to atomic mass. Similar elements were arranged together in a “group”.
- 23. Mendeleev • Father of the Periodic Table • Periodic Law- Both physical and chemical properties of the elements vary periodically with increasing atomic mass. • Exception placed Te (M = 127.6) a head of I (M=126.9) because Te was similar to Se and S, and I was similar to Cl and Br. • Left gaps in periodic table and predicted new elements would be found. Predicted the new elements’ properties.
- 24. Periods of Elements •Periods of elements are the horizontal rows of the Periodic Table. •The properties of the elements vary as you move from left to right across the periods. •On the left, the periodic table starts with shiny reactive metals, followed by dull solids and reactive non-metals. Each period ends with a non-reactive noble gas
- 25. Valence Electrons •Starting with one valence electron for the first element in a period, the number of electrons increases as you move from left to right across a period. •The periodic changes in properties of elements coincide with their placement in the periodic table.
- 26. Groups and Families •Vertical columns of elements in the periodic table are called groups or families. •Elements in the same group or family have similar chemical properties. •Representative Elements are those in the first two groups and the last six groups (s-block and p-block) in the periodic table. These groups are designated 1,2,13-18 or the A group elements
- 27. Electron Configurations can be Determined From the Position in the Periodic Table: •Elements in group 1(1A) end in ns1 . •Elements in group 2 (2A): end in ns2 •Elements in group 13 (3A) end in ns2 np1 •Elements in group 14 (4A): end in ns2 np2 •Elements in group 15 (5A) end in ns2 np3 •Elements in group 16 (6A) end in ns2 np4 •Elements in group 17 (7A) end in ns2 np5 •Elements in group 18 (8A) end in ns2 np6
- 28. Periodic Trends in Properties of Elements •Various Elemental Properties change fairly smoothly going across a period or down a group. •Properties include: –Atomic and Ionic Radius –Ionization Energy –Melting Points and Boiling Points –Density and Conductivity
- 29. Atomic Size of Elements –Atomic size (radius) is based on the average distance between the outer electrons and the nucleus. –A measure of atomic size is the Atomic Radius (AR). –AR decreases as you move from left to right across a period. –AR increases as you move down a group
- 30. Trends in Atomic Radius
- 31. Relative Radii of Atoms
- 32. Periodic Trends in Atomic Radius
- 33. Ionic Radius •When anions are formed, electron(s) are added, the radius increases. •When cations are formed, electron(s) are lost, the radius decreases. •Ionic radius decreases going down a group. •Going from left to right across a period ionic radius decreases for cations, then increases for anions, then decreases.
- 34. Comparing the Size of Atoms and Ions
- 35. Shielding Effect
- 36. Ionization Energy •Ionization Energy (or Ionization Potential) –Ionization Energy (IE) is the energy required to remove one mole of electrons from one mole of gaseous atoms or ions. Na + IE Na+ + e- •IE increases (irregularly) as you move from left to right across a period. •IE decreases (irregularly) as you move down a group.
- 37. Trend in Ionization Energy
- 38. Electronegativity • Electronegativity is a measure of attraction an atom has for bonding electrons or how badly the atom wants another electron. The higher the electronegativity, the more desperate for an electron the atom is. • Electronegativity increases from left to right across a period. • The closer the valence shell is to full, the stronger the pull of that atom on the electrons in a bonding pair. Electronegativity decreases down a group. • The further the valence electron shell is from the nucleus of an atom, the weaker the pull of the atom on the electrons in a bonding pair. Noble gases have a complete valance shell so they do not attract electrons.
- 39. Electron affinity • Electron affinity is the ability of an atom to accept an electron. This is a quantitative measurement of the energy change occurring when an electron is added to a neutral gas atom. • Like ionization energy, there is an electron affinity measured for an atom for each successive electron added.
- 40. Trend • Tend to be negative, meaning energy is released when the electron is added. • The amount of energy released increases left to right across a period. • The amount of energy released decreases down a group. • The noble gases have positive first electron affinities, meaning they require energy to accept an electron.
Editor's Notes
- #5: “Periodic Table of Elements” image – linked to a webpage that has an interactive Periodic Table that can be clicked on for more information about each element in detail. May or may not be used during lesson. Click the outer, black edges of the slide during presentation if you do not wish to link to the webpage.
- #20: Answer: Oxygen for respiration, Nitrogen in the atmosphere, Copper in pennies, Sodium and Chlorine for salt, Hydrogen and Oxygen for water, Aluminum foil for food.