Periodic Table

1. Periodic Table The Atom and the Elements

2. Periodic Table • In 1872, Dmitri Mendeleev arranged the 60 known elements into columns or groups with similar properties.

3. Periodic Table • Today’s periodic table contains 117 elements arranged in order of increasing atomic number.

4. PERIODIC TABLE • Arranges similar elements together in patterns • Arranged by the # of protons or atomic number • Helps predict properties of an element PERIODIC LAW – states that when elements are arranged in order by # of protons, similarities in properties will occur in a pattern

5. Today’s Element List • 10 = 99% of the mass of the Earth (5=92%) (O,Si,H, Al, Fe, Ca,Na,Mg, Cl,K)

6. Metals Shiny Solids Stretched and Shaped Conductors of heat and electricity Nonmetals Solids, liquids or gases Solids – dull and brittle Poor conductors of heat and electricity ****Semiconductors / Metalloids – exhibit properties of both metals and nonmetals FAMILIES OF ELEMENTS

9. How do you tell if it’s a metal, nonmetal, or metalloid? • Metals • On the left hand side of the zigzag line (except for Hydrogen – exception) - Metalloids or Semi-metals - Touching zigzag line (Except for Al) - Exhibit properties of both metals and nonmetals • Nonmetals • On the right hand side of the zigzag line (plus Hydrogen)

10. How would you classify calcium? • Metal • Nonmetal • Metalloid

11. How would you classify arsenic? • Metal • Nonmetal • Metalloid

12. How would you classify carbon? • Metal • Nonmetal • Metalloid

13. GROUPS PERIOD To keep table shorter/ in line

15. GROUPS • Columns of the periodic table • Atoms of elements in the same group have the same # of valence electrons and therefore behave similarly PERIODS • Rows of the periodic table • All elements in a period have the • their valence electrons in the same energy level.

16. Which of the following are in the same group? • H, He, C, Li • K, Ca, As, Br • He, Ne, Kr, Ar • B, Al, Ge, Sn

17. Which of the following are in the same period? • H, He, C, Li • K, Ca, As, Br • He, Ne, Kr, Ar • B, Al, Ge, Sn

18. Representative and Transition Elements

19. METALS • 4 Different kinds of metals • Alkali metals: soft, shiny and very reactive • Group 1: not found in nature as elements • Alkaline earth-metals: less reactive • Group 2: have two valence electrons • Transition Metals: many uses • Groups 3-12

20. NONMETALS • 3 Different kinds of metals • Noble Gases: mostly non-reactive, very stable • Group 8: He, Ne, Ar, Kr, Xe, Rn • Halogens: very reactive, gain one electron to form a stable compound • Group 7: F, Cl, Br, I

21. Diatomic Gases • Seven elements are called diatomic and never exist alone in nature. • Have No Fear Of Ice Cold Beans????? • H2 • N2 • F2 • O2 • I2 • Cl2 • Br2

22. Magnesium is in which group? • Alkali metals • Alkaline earth metals • Transition metals • Halogens • Noble gases

23. Lithium is in which group? • Alkali metals • Alkaline earth metals • Transition metals • Halogens • Noble gases

24. Manganese is in which group? • Alkali metals • Alkaline earth metals • Transition metals • Halogens • Noble gases

25. Krypton is in which group? • Alkali metals • Alkaline earth metals • Transition metals • Halogens • Noble gases

26. The majority of the diatomic gases are in which group? • Alkali metals • Alkaline earth metals • Transition metals • Halogens • Noble gases

27. Democritus • 1st to “think” of atoms • Derived from Greek word – “unable to be divided” • Called them - atomos • 4th century BC

28. John Dalton • 1808 • Created the atomic theory. Educated himself age 12 became a school teacher

29. Dalton’s Atomic Theory • 1) All matter is made up of atoms. • 2) All atoms of an element are identical to each other and different from other elements. • 3) Atoms of different elements combine in the same ratio of the same elements to form compounds. • 4) A chemical reaction involves the rearrangement of atoms. Atoms are never created nor destroyed in these reactions.

30. Atomic Theory through Time 400 BC Democritus • John Dalton: • D. Mendeleev: organizes periodic table 1897 JJ Thompson • ErnestRutherford • Niels Bohr 1923 Louis de Broglie 1930 Erwin Schrodinger

31. JJ Thomson • experimented with currents of electricity inside empty glass tubes. • Discovered • electron in every atom • electrons have a negative charge • “Plum-pudding” model

32. Ernest Rutherford Geiger and Marsden Lab 18.1 – Gold Foil Experiment

33. Rutherford •  particles • most passed straight through • Atom mostly empty space ! • some scattered at large angles • Center positively charged nucleus that is extremely dense.

34. Niels Bohr Electrons in an atom move inin a set paths or orbitsaround the nucleus / similar to planets orbiting around the sun Orbits have fixed amount of energy

35. Louis deBroglie • By 1925 Bohr’s Model was altered. • Electrons behave like waves as well as like particles – wave-particle duality theory of matter • Helped develop quantum mechanics

36. Erwin Schrodinger • Modified Bohr’s theory to state that electrons are not in fixed orbits but in continuous clouds – quantum mechanical model

37. Subatomic Particles • Subatomic particles include the proton, neutron, and electron

38. Which of the following does not exist in the nucleus? • Proton • Neutron • Electron

39. Which of the following has a mass much less than the other two particles? • Proton • Neutron • Electron

40. Which of the following has an electric charge of zero? • Proton • Neutron • Electron

41. Key terms of atomic structure • Atomic Number (Z) = number of protons • Each element has its own unique atomic number • Mass number = sum of protons and neutrons = mass of the nucleus

42. Isotope Notation • Isotopes are forms of the same element (same number of protons) with differing numbers of neutrons

43. How many protons are in the following isotope? • 19 • 9 • 10

44. How many neutrons are in the following isotope? • 19 • 9 • 10