2. Development of the Periodic Table Chapter 5 Section 1

3. Measurable Goal: 10B: Evaluate the properties of the Periodic Table Honors: Determine solubility and reactivity within the alkaline earth family and relate the reactions to the Periodic Table

4. Timeline overview: Periodic Table Dobereiner (1800s)-triad (two sets of three) Newland (1865)-octaves Meyer and Mendeleev (1869)- arranged in order of increasing atomic mass *Mendeleev believed that the atomic mass had been miscalculated but in actuality the atomic # was not thought of until Moseley (Rutherford student)

5. What is an ELEMENT? o A substance composed of a single kind of atom. o Cannot be broken down into another substance by chemical or physical means.

6. Elements Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth. Scientists have identified 90 naturally occurring elements, and created about 28 others.

7. I am Dmitri Mendeleev! I made the PERIODIC TABLE !

8. What is the PERIODIC TABLE? o Shows all known elements in the universe. o Organizes the elements by chemical properties.

9. How do you read the PERIODIC TABLE?

10. What is the ATOMIC NUMBER? o The number of protons found in the nucleus of an atom Or o The number of electrons surrounding the nucleus of an atom.

11. What is the SYMBOL? o An abbreviation of the element name.

12. Symbols All elements have their own unique symbol. It can consist of a single capital letter, or a capital letter and one or two lower case letters. C Carbon Cu Copper

13. What is the ATOMIC WEIGHT? o The number of protons and neutrons in the nucleus of an atom.

14. How do I find the number of protons, electrons, and neutrons in an element using the periodic table? o # of PROTONS = ATOMIC NUMBER o # of ELECTRONS = ATOMIC NUMBER o # of NEUTRONS = ATOMIC _ ATOMIC WEIGHT NUMBER WEIGHT NUMBER

15. Periodic Law The periodic table organizes the elements in a particular way. A great deal of information about an element can be gathered from its position in the period table. Periodic law- when elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic trend

16. Common Elements and Symbols

19. Thursday 10-29-15 Measurable Goal: Evaluate the properties of the Periodic Table Week 4: DSQ 1: What is the periodic table and who developed it?

20. Families Periods Columns of elements are called groups or families. For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals. All elements in a family have the same number of valence electrons. Each horizontal row of elements is called a period. The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.

21. Atomic Mass Unit (AMU) The unit of measurement for an atom is an AMU. It stands for atomic mass unit. One AMU is equal to the mass of one proton.

22. Atomic Mass Unit (AMU) There are 6 X 10 23 or 600,000,000,000,000, 000,000,000 amus in one gram. (Avogadro’s Number)

23. Put on piece of paper to turn in today pg 188 #1,3, 10, 11 189 #28 (3 to 5 sentences)

24. Add common trends (atomic radius, valence electrons), ionization, electronegativity

25. Periodic Trends Elemental Properties and Patterns

26. The Periodic Law Dimitri Mendeleev was the first scientist to publish an organized periodic table of the known elements. He was perpetually in trouble with the Russian government and the Russian Orthodox Church, but he was brilliant never-the-less.

27. The Periodic Law Mendeleev even went out on a limb and predicted the properties of 2 at the time undiscovered elements. He was very accurate in his predictions, which led the world to accept his ideas about periodicity and a logical periodic table.

28. The Periodic Law Mendeleev understood the ‘Periodic Law’ which states: When arranged by increasing atomic number, the chemical elements display a regular and repeating pattern of chemical and physical properties.

29. The Periodic Law Atoms with similar properties appear in groups or families (vertical columns) on the periodic table. They are similar because they all have the same number of valence (outer shell) electrons, which governs their chemical behavior.

30. Valence Electrons Do you remember how to tell the number of valence electrons for elements in the s- and p-blocks? How many valence electrons will the atoms in the d-block (transition metals) and the f- block (inner transition metals) have? Most have 2 valence e-, some only have 1.

31. A Different Type of Grouping Besides the 4 blocks of the table, there is another way of classifying element: Metals Nonmetals Metalloids or Semi-metals. The following slide shows where each group is found.

32. Metals, Nonmetals, Metalloids

33. There is a zig-zag or staircase line that divides the table. Metals are on the left of the line, in blue. Nonmetals are on the right of the line, in orange.

34. Metals, Nonmetals, Metalloids Elements that border the stair case, shown in purple are the metalloids or semi- metals. There is one important exception. Aluminum is more metallic than not.

35. Metals, Nonmetals, Metalloids How can you identify a metal? What are its properties? What about the less common nonmetals? What are their properties? And what the heck is a metalloid?

36. Metals Metals are lustrous (shiny), malleable, ductile, and are good conductors of heat and electricity. They are mostly solids at room temp. What is one exception?

37. Nonmetals Nonmetals are the opposite. They are dull, brittle, nonconductors (insulators). Some are solid, but many are gases, and Bromine is a liquid.

38. Metalloids Metalloids, aka semi-metals are just that. They have characteristics of both metals and nonmetals. They are shiny but brittle. And they are semiconductors. What is our most important semiconductor?

39. Periodic Trends There are several important atomic characteristics that show predictable trends that you should know. The first and most important is atomic radius. Radius is the distance from the center of the nucleus to the “edge” of the electron cloud.

40. Atomic Radius Since a cloud’s edge is difficult to define, scientists use define covalent radius, or half the distance between the nuclei of 2 bonded atoms. Atomic radii are usually measured in picometers (pm) or angstroms (Å). An angstrom is 1 x 10 -10 m.

41. Covalent Radius Two Br atoms bonded together are 2.86 angstroms apart. So, the radius of each atom is 1.43 Å. 2.86 Å 1.43 Å

42. Atomic Radius The trend for atomic radius in a vertical column is to go from smaller at the top to larger at the bottom of the family. Why? With each step down the family, we add an entirely new PEL to the electron cloud, making the atoms larger with each step.

43. Atomic Radius The trend across a horizontal period is less obvious. What happens to atomic structure as we step from left to right? Each step adds a proton and an electron (and 1 or 2 neutrons). Electrons are added to existing PELs or sublevels.

44. Atomic Radius The effect is that the more positive nucleus has a greater pull on the electron cloud. The nucleus is more positive and the electron cloud is more negative. The increased attraction pulls the cloud in, making atoms smaller as we move from left to right across a period.

45. Effective Nuclear Charge What keeps electrons from simply flying off into space? Effective nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus, the more pull it feels. As effective nuclear charge increases, the electron cloud is pulled in tighter.

46. Atomic Radius The overall trend in atomic radius looks like this.

47. Atomic Radius Here is an animation to explain the trend. On your help sheet, draw arrows like this:

48. Shielding As more PELs are added to atoms, the inner layers of electrons shield the outer electrons from the nucleus. The effective nuclear charge (enc) on those outer electrons is less, and so the outer electrons are less tightly held.

49. Ionization Energy This is the second important periodic trend. If an electron is given enough energy (in the form of a photon) to overcome the effective nuclear charge holding the electron in the cloud, it can leave the atom completely. The atom has been “ionized” or charged. The number of protons and electrons is no longer equal.

50. Ionization Energy The energy required to remove an electron from an atom is ionization energy. (measured in kilojoules, kJ) The larger the atom is, the easier its electrons are to remove. Ionization energy and atomic radius are inversely proportional. Ionization energy is always endothermic, that is energy is added to the atom to remove the electron.

51. Ionization Energy

52. Ionization Energy (Potential) Draw arrows on your help sheet like this:

53. Electron Affinity What does the word ‘affinity’ mean? Electron affinity is the energy change that occurs when an atom gains an electron (also measured in kJ). Where ionization energy is always endothermic, electron affinity is usually exothermic, but not always.

54. Electron Affinity Electron affinity is exothermic if there is an empty or partially empty orbital for an electron to occupy. If there are no empty spaces, a new orbital or PEL must be created, making the process endothermic. This is true for the alkaline earth metals and the noble gases.

55. Electron Affinity Your help sheet should look like this: ++

56. Metallic Character This is simple a relative measure of how easily atoms lose or give up electrons. Your help sheet should look like this:

57. Electronegativity Electronegativity is a measure of an atom’s attraction for another atom’s electrons. It is an arbitrary scale that ranges from 0 to 4. The units of electronegativity are Paulings. Generally, metals are electron givers and have low electronegativities. Nonmetals are are electron takers and have high electronegativities. What about the noble gases?

58. Electronegativity Your help sheet should look like this: 0

59. Overall Reactivity This ties all the previous trends together in one package. However, we must treat metals and nonmetals separately. The most reactive metals are the largest since they are the best electron givers. The most reactive nonmetals are the smallest ones, the best electron takers.

60. Overall Reactivity Your help sheet will look like this: 0

61. The Octet Rule The “goal” of most atoms (except H, Li and Be) is to have an octet or group of 8 electrons in their valence energy level. They may accomplish this by either giving electrons away or taking them. Metals generally give electrons, nonmetals take them from other atoms. Atoms that have gained or lost electrons are called ions.

62. Ions When an atom gains an electron, it becomes negatively charged (more electrons than protons ) and is called an anion. In the same way that nonmetal atoms can gain electrons, metal atoms can lose electrons. They become positively charged cations.

63. Ions Here is a simple way to remember which is the cation and which the anion: This is a cat-ion. This is Ann Ion. He’s a “plussy” cat! She’s unhappy and negative. +

64. Ionic Radius Cations are always smaller than the original atom. The entire outer PEL is removed during ionization. Conversely, anions are always larger than the original atom. Electrons are added to the outer PEL.

65. Cation Formation 11p+ Na atom 1 valence electron Valence e- lost in ion formation Effective nuclear charge on remaining electrons increases. Remaining e- are pulled in closer to the nucleus. Ionic size decreases. Result: a smaller sodium cation, Na +

66. Anion Formation 17p+ Chlorine atom with 7 valence e- One e- is added to the outer shell. Effective nuclear charge is reduced and the e- cloud expands. A chloride ion is produced. It is larger than the original atom.

68. Properties of Metals Metals are good conductors of heat and electricity. Metals are shiny. Metals are ductile (can be stretched into thin wires). Metals are malleable (can be pounded into thin sheets). A chemical property of metal is its reaction with water which results in corrosion.

69. Properties of Non-Metals Non-metals are poor conductors of heat and electricity. Non-metals are not ductile or malleable. Solid non-metals are brittle and break easily. They are dull. Many non-metals are gases. Sulfur

70. Properties of Metalloids Metalloids (metal-like) have properties of both metals and non-metals. They are solids that can be shiny or dull. They conduct heat and electricity better than non- metals but not as well as metals. They are ductile and malleable. Silicon

71. Hydrogen The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is in a class of its own. It’s a gas at room temperature. It has one proton and one electron in its one and only energy level. Hydrogen only needs 2 electrons to fill up its valence shell.

72. Alkali Metals The alkali family is found in the first column of the periodic table. Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron. They are shiny, have the consistency of clay, and are easily cut with a knife.

73. Alkali Metals They are the most reactive metals. They react violently with water. Alkali metals are never found as free elements in nature. They are always bonded with another element.

74. What does it mean to be reactive? We will be describing elements according to their reactivity. Elements that are reactive bond easily with other elements to make compounds. Some elements are only found in nature bonded with other elements. What makes an element reactive?  An incomplete valence electron level.  All atoms (except hydrogen) want to have 8 electrons in their very outermost energy level (This is called the rule of octet.)  Atoms bond until this level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.

75. Alkaline Earth Metals They are never found uncombined in nature. They have two valence electrons. Alkaline earth metals include magnesium and calcium, among others.

76. Transition Metals Transition Elements include those elements in the B families. These are the metals you are probably most familiar: copper, tin, zinc, iron, nickel, gold, and silver. They are good conductors of heat and electricity.

77. Transition Metals The compounds of transition metals are usually brightly colored and are often used to color paints. Transition elements have 1 or 2 valence electrons, which they lose when they form bonds with other atoms. Some transition elements can lose electrons in their next-to-outermost level.

78. Transition Elements Transition elements have properties similar to one another and to other metals, but their properties do not fit in with those of any other family. Many transition metals combine chemically with oxygen to form compounds called oxides.

79. Boron Family The Boron Family is named after the first element in the family. Atoms in this family have 3 valence electrons. This family includes a metalloid (boron), and the rest are metals. This family includes the most abundant metal in the earth’s crust (aluminum).

80. Carbon Family Atoms of this family have 4 valence electrons. This family includes a non-metal (carbon), metalloids, and metals. The element carbon is called the “basis of life.” There is an entire branch of chemistry devoted to carbon compounds called organic chemistry.

81. Nitrogen Family The nitrogen family is named after the element that makes up 78% of our atmosphere. This family includes non- metals, metalloids, and metals. Atoms in the nitrogen family have 5 valence electrons. They tend to share electrons when they bond. Other elements in this family are phosphorus, arsenic, antimony, and bismuth.

82. Oxygen Family Atoms of this family have 6 valence electrons. Most elements in this family share electrons when forming compounds. Oxygen is the most abundant element in the earth’s crust. It is extremely active and combines with almost all elements.

83. Halogen Family The elements in this family are fluorine, chlorine, bromine, iodine, and astatine. Halogens have 7 valence electrons, which explains why they are the most active non- metals. They are never found free in nature. Halogen atoms only need to gain 1 electron to fill their outermost energy level. They react with alkali metals to form salts.

84. Noble Gases Noble Gases are colorless gases that are extremely un- reactive. One important property of the noble gases is their inactivity. They are inactive because their outermost energy level is full. Because they do not readily combine with other elements to form compounds, the noble gases are called inert. The family of noble gases includes helium, neon, argon, krypton, xenon, and radon. All the noble gases are found in small amounts in the earth's atmosphere.

85. Rare Earth Elements The thirty rare earth elements are composed of the lanthanide and actinide series. One element of the lanthanide series and most of the elements in the actinide series are called trans-uranium, which means synthetic or man-made.

86. Mendeleev In 1869, Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties. Blank spaces were left open to add the new elements he predicted would occur.

87. Matter All matter is composed of atoms and groups of atoms bonded together, called molecules.  Substances that are made from one type of atom only are called pure substances.  Substances that are made from more than one type of atom bonded together are called compounds.  Compounds that are combined physically, but not chemically, are called mixtures.

88. Elements, Compounds, Mixtures Sodium is an element. Chlorine is an element. When sodium and chlorine bond they make the compound sodium chloride, commonly known as table salt.  Compounds have different properties than the elements that make them up.  Table salt has different properties than sodium, an explosive metal, and chlorine, a poisonous gas.

89. Elements, Compounds, Mixtures Hydrogen is an element. Oxygen is an element. When hydrogen and oxygen bond they make the compound water. When salt and water are combined, a mixture is created. Compounds in mixtures retain their individual properties. The ocean is a mixture.

90. Elements, compounds, and mixtures Mixtures can be separated by physical means. Compounds can only be separated by chemical means. Elements are pure substances. When the subatomic particles of an element are separated from its atom, it no longer retains the properties of that element.