1. Chapter 5 : The Periodic Table

2. Objectives Be able to define and explain each periodic trend, including comparing two different elements. For example: which of the following elements has the larger atomic radius? Be able to define and explain each periodic trend, including comparing two different elements. For example: which of the following elements has the larger atomic radius?

3. History of the Periodic Table In the 1700s scientists had identified only 30 elements In the 1700s scientists had identified only 30 elements In the 1800s there were 60 In the 1800s there were 60

4. History of the Periodic Table Early 1800s Dobereiner grouped elements into triads by physical and chemical properties Early 1800s Dobereiner grouped elements into triads by physical and chemical properties Li, Na, K Li, Na, K

5. History of the Periodic Table 1865 J.A.R. Newlands discovered that when elements were arranged by atomic mass, properties repeated themselves every eighth element 1865 J.A.R. Newlands discovered that when elements were arranged by atomic mass, properties repeated themselves every eighth element Called these octaves Called these octaves

6. Mendeleev 1869 Dmitri Mendeleev produced the first periodic table for his students 1869 Dmitri Mendeleev produced the first periodic table for his students Left blanks where elements had yet to be discovered Left blanks where elements had yet to be discovered Not strictly in order of atomic mass (Ar  K) Not strictly in order of atomic mass (Ar  K)

8. Properties of Germanium as Predicted by Mendeleev Properties of Ekasilicon Predicted in 1871 Atomic weight Density Specific heat Melting point Oxide formula Oxide density Chloride formula bp of chloride 72 5.5 g/cm 3 0.31 J/(°C · g) Very high RO 2 4.7 g/cm 3 RCl 4 100°C

9. Properties of Germanium Predicted in 1871 Observed in 1886 Atomic weight Density Specific heat Melting point Oxide formula Oxide density Chloride formula bp of chloride 72 5.5 g/cm 3 0.31 J/(°C · g) Very high RO 2 4.7 g/cm 3 RCl 4 100°C 72.3 5.47 g/cm 3 0.32 J/(°C · g) 960°C GeO 2 4.70 g/cm 3 GeCl 4 86°C

10. Moseley In 1913 Moseley assigned elements atomic numbers and rearranged periodic table In 1913 Moseley assigned elements atomic numbers and rearranged periodic table Periodic Law – when arranged by increasing atomic number elements show periodic trends Periodic Law – when arranged by increasing atomic number elements show periodic trends

11. Table Terms Groups or Families are the columns on the periodic table Groups or Families are the columns on the periodic table Periods are the rows going across. Periods are the rows going across.

12. Periodic Properties Depend on two main factors: the number of protons and electrons, and the way these subatomic particles interact with each other. Depend on two main factors: the number of protons and electrons, and the way these subatomic particles interact with each other.

13. Draw a Bohr Model for Lithium Lithium Potassium Potassium Fluorine Fluorine Make sure to indicate the number of protons in the center Make sure to indicate the number of protons in the center Make sure levels are the same size from atom to atom (rings for energy levels should be the same size) Make sure levels are the same size from atom to atom (rings for energy levels should be the same size)

14. Lithium

15. Potassium

16. Fluorine

17. Atomic Radius Atomic radius is the distance from the atom’s nucleus to its outer edge. Atomic radius is the distance from the atom’s nucleus to its outer edge. Simply can be thought of as the size of an atom Simply can be thought of as the size of an atom Using the Bohr model, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your answers Using the Bohr model, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your answers Which atom has a larger atomic radius: lithium or potassium? Which atom has a larger atomic radius: lithium or potassium? Which atom has a larger atomic radius: lithium or fluorine? Which atom has a larger atomic radius: lithium or fluorine? What is the atomic radius ____ from left to right on the periodic table. What is the atomic radius ____ from left to right on the periodic table. What is the atomic radius ____ from top to bottom on the periodic table. What is the atomic radius ____ from top to bottom on the periodic table.

19. Atomic Radius Atoms get larger going down a group or family Atoms get larger going down a group or family –Principle energy level increases moving down Atoms get smaller moving from left to right Atoms get smaller moving from left to right –In the same energy level, more protons exert a stronger pull towards the nucleus

20. Ionization Energy Ionization energy is the energy needed to remove one electron Ionization energy is the energy needed to remove one electron Na(g) -> Na + (g) + 1e - Na(g) -> Na + (g) + 1e - Remember that an ion is a atom with an overall charge of negative or positive (number of electrons changes) Remember that an ion is a atom with an overall charge of negative or positive (number of electrons changes) Metals are more likely to give up an electron than nonmetals. Metals are more likely to give up an electron than nonmetals. The more difficult it is to remove an electron the higher the ionization energy will be. The more difficult it is to remove an electron the higher the ionization energy will be.

21. Ionization Using the Bohr models, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your anwsers. Using the Bohr models, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your anwsers. Which atom has a higher ionization energy: lithium or potassium? Which atom has a higher ionization energy: lithium or potassium? Which atom has a higher ionization energy: lithium or fluorine? Which atom has a higher ionization energy: lithium or fluorine? Ionization energy______ from left to right on the perioidic table Ionization energy______ from left to right on the perioidic table Ionication energy _______from top to bottom on the periodic table Ionication energy _______from top to bottom on the periodic table

22. Ionization Energy Ionization energy is the energy needed to remove one electron Ionization energy is the energy needed to remove one electron Na(g) -> Na + (g) + 1e - Na(g) -> Na + (g) + 1e - Metals are more likely to give up an electron than nonmetals. Metals are more likely to give up an electron than nonmetals. IE decreases when moving down the group IE decreases when moving down the group IE increases moving from left to right in a period IE increases moving from left to right in a period There are second and third IEs for the next electrons There are second and third IEs for the next electrons

24. Electron Affinity Electron affinity is the energy change that occurs when an atom gains an electron Electron affinity is the energy change that occurs when an atom gains an electron F(g) + e -  F - (g) F(g) + e -  F - (g) Most atoms give off energy when an electron is gained (negative) Most atoms give off energy when an electron is gained (negative) Nonmetals have more of an electron affinity than metals Nonmetals have more of an electron affinity than metals Atoms with greater affinity are more able to gain valance electrons Atoms with greater affinity are more able to gain valance electrons

25. Electron Affinity Using the Bohr models, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your answers. Using the Bohr models, and thinking about the number, arrangement, and interaction of the protons and electrons, answer the following questions, and explain your answers. Which atom has a greater electron affinity: lithium or potassium? Which atom has a greater electron affinity: lithium or potassium? Which atom has a greater electron affinity: lithium or fluorine? Which atom has a greater electron affinity: lithium or fluorine? Electron affinity _______ from left to right on the periodic table. Electron affinity _______ from left to right on the periodic table. Electron affinity ______from top to bottom on the periodic table Electron affinity ______from top to bottom on the periodic table

26. Electron affinity EA decreases when moving down the group EA decreases when moving down the group EA increases moving from left to right in a period EA increases moving from left to right in a period

28. Electronegativity Electronegativity reflects an atom’s ability to attract electrons Electronegativity reflects an atom’s ability to attract electrons It is defined as the ability of an atom in a molecule to attract electrons. It is defined as the ability of an atom in a molecule to attract electrons. Example: if a molecule consists of atoms X bonded to atom Y. Example: if a molecule consists of atoms X bonded to atom Y. X-Y X-Y The two atoms share the electrons in the molecule. If X is more electronegative than Y, then the electrons will be more strongly attracted to X than Y, and will “hog” the electrons The two atoms share the electrons in the molecule. If X is more electronegative than Y, then the electrons will be more strongly attracted to X than Y, and will “hog” the electrons X – Y X – Y

29. Electronegativity Which atom has a greater electronegativity: lithium or potassium? Which atom has a greater electronegativity: lithium or potassium? Which atom has a greater electronegativity: lithium or fluorine? Which atom has a greater electronegativity: lithium or fluorine? Electronegativity _______ from left to right on the periodic table. Electronegativity _______ from left to right on the periodic table. Electronegativity______ from top to bottom on the periodic table Electronegativity______ from top to bottom on the periodic table

30. Electronegativity Cs & Fr have the lowest electronegativities; F has the highest Cs & Fr have the lowest electronegativities; F has the highest EN decreases when moving down the group EN decreases when moving down the group EN increases when moving from left to right across the period EN increases when moving from left to right across the period

32. Ionic Radius Ionic radius is the distance from the ion’s nucleus to its outer edge. Ionic radius is the distance from the ion’s nucleus to its outer edge. Remember that positive ions are formed when atoms lose electrons Remember that positive ions are formed when atoms lose electrons Negative ions are formed when atoms gain electrons Negative ions are formed when atoms gain electrons Ions get larger going down a group or family Ions get larger going down a group or family Ions get larger moving from left to right Ions get larger moving from left to right –The more electrons added increases repulsion among them

33. Draw the Bohr models for the following: Lithium and Lithium ion (+) Lithium and Lithium ion (+) How does the lithium ion’s radius compare to the radius of neutral lithium? How does the lithium ion’s radius compare to the radius of neutral lithium? Chlorine and Chlorine ion (-) Chlorine and Chlorine ion (-) How does the chloride ion’s radius compare to the radius of neutral chlorine? How does the chloride ion’s radius compare to the radius of neutral chlorine? Sodium ion (+) and Fluoride Ion (-) Sodium ion (+) and Fluoride Ion (-) How do the number of electrons in these two ions compare to each other? How do the number of electrons in these two ions compare to each other? How do the radii of these two ions compare to each other? How do the radii of these two ions compare to each other?

34. Ionic radius Ions get larger going down a group or family Ions get larger going down a group or family Ions get larger moving from left to right Ions get larger moving from left to right –The more electrons added increases repulsion among them

37. Major Groups on the Periodic Table Alkali Metals Alkali Metals Alkaline Earth Metals Alkaline Earth Metals Transition Metals Transition Metals Boron Group Boron Group Carbon Group Carbon Group Nitrogen Group Nitrogen Group Oxygen Group (Chalcogens) Oxygen Group (Chalcogens) Halogens Halogens Noble Gases Noble Gases Actinide Series Actinide Series Lanthanide Series Lanthanide Series

38. Reactivity of Alkali and Alkaline Earth Metals Metals become more reactive as you move down the group Metals become more reactive as you move down the group Metals become less active when moving left to right Metals become less active when moving left to right

39. Why Are There Patterns? Elements have physical and chemical properties based upon their valence electrons. Elements have physical and chemical properties based upon their valence electrons. Valence electrons are the electrons in the outer most energy level (s & p orbitals) Valence electrons are the electrons in the outer most energy level (s & p orbitals) The number of valence electrons may be determined by using the periodic table The number of valence electrons may be determined by using the periodic table

40. Why Are There Patterns? When you look at an atom you are observing the valence electrons When you look at an atom you are observing the valence electrons Duet rule - only 2 electrons fill the first energy level Duet rule - only 2 electrons fill the first energy level Octet rule – 8 valence electrons is considered to be a full set Octet rule – 8 valence electrons is considered to be a full set