1. Chapter 6
The Periodic Table

2. Section 1
Development of the Modern Periodic Table

3. Section 1: Development of the Modern Periodic Table
The periodic table evolved over time as scientists discovered more useful ways to compare and organize the elements. K
What I Know W
What I Want to Find Out L
What I Learned

4. The History of the Periodic Table

5. In 1750, only 17 elements were known.
As the rate of discovery increased, so did the need to organize the elements
In 1789 Antoine Lavoisier grouped the known elements into metals, nonmetals, gases, and earths.

6. Development of the Periodic Table
In the 1700s, Lavoisier compiled a list of all the known elements of the time.
Development of the Modern Periodic Table

7. Development of the Periodic Table
The 1800s brought large amounts of information and scientists needed a way to organize knowledge about elements.
John Newlands proposed an arrangement where elements were ordered by increasing atomic mass.
Development of the Modern Periodic Table

8. Development of the Periodic Table
Newlands noticed when the elements were arranged by increasing atomic mass, their properties repeated every eighth element.
Development of the Modern Periodic Table

9. Development of the Periodic Table
Meyer and Mendeleev both demonstrated a connection between atomic mass and elemental properties.
Moseley rearranged the table by increasing atomic number, and resulted in a clear periodic pattern.
Periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic number is called periodic law.
Development of the Modern Periodic Table

10. Mendeleev’s Periodic Table
 Medeleev made flash cards of the 63 known elements. (1863)
On each card he put the name of the element, mass, and properties.
When he lined the cards up in order of increasing mass, a pattern emerged.
Mendeleev arranged the elements into row in order of increasing mass so that elements with similar properties were in the same column.
A deck of cards can be divided into four suits—diamonds, spades, hearts, and clubs. In one version of solitaire, a player must produce an arrangement in which each suit is ordered from ace to king. This arrangement is a model for Mendeleev's periodic table.

11. Periodic Table- Arrangement of elements in columns, based on a set of properties that repeat from row to row.
Mendeleev’s Prediction
He could not make a complete table because many of the elements had not yet been discovered. He had to leave spaces for those elements.
Eka-Aluminum – one space below Al. He predicted it would be a soft metal with a low m.p. and a density of 5.9 g/cm3
The close match between Mendeleev’s prediction and the actual properties of new elements showed how useful the periodic table could be.
Gallium was discovered in It’s a soft metal, m.p. is 29.7 ˚C, and has a density of 5.91 g/cm3
Heat from a person's hand can melt gallium. In some traffic signals, there are tiny light emitting diodes (LEDs) that contain a compound of gallium

13. Mendeleev’s Periodic Table
How is the table organized?
Elements are arranged in order of increasing mass.
What do the long dashes represent?
They represent undiscovered elements.
Why are masses listed with some of the dashes, but not with all of them?
He was able to predict properties for some unknown elements based on the properties of neighboring elements.

14. Development of the Modern Periodic Table

15. The Modern Periodic Table
The modern periodic table contains boxes that contain the element's name, symbol, atomic number, and atomic mass.
Development of the Modern Periodic Table

16. The Modern Periodic Table
Columns of elements are called groups.
Rows of elements are called periods.
Elements in groups 1,2, and 13–18 possess a wide variety of chemical and physical properties and are called the representative elements.
Elements in groups 3–12 are known as the transition metals.
Development of the Modern Periodic Table

17. The Modern Periodic Table
Elements are classified as metals, nonmetals, and metalloids.
Metals are elements that are generally shiny when smooth and clean, solid at room temperature, and good conductors of heat and electricity.
Alkali metals are all the elements in group 1 except hydrogen, and are very reactive.
Alkaline earth metals are in group 2, and are also highly reactive.
Development of the Modern Periodic Table

18. The Modern Periodic Table
The transition elements are divided into transition metals and inner transition metals.
The two sets of inner transition metals are called the lanthanide series and actinide series and are located at the bottom of the periodic table.
Development of the Modern Periodic Table

19. The Modern Periodic Table
Nonmetals are elements that are generally gases or brittle, dull-looking solids, and poor conductors of heat and electricity.
Group 17 is composed of highly reactive elements called halogens.
Group 18 gases are extremely unreactive and commonly called noble gases.
Metalloids, such as silicon and germanium, have physical and chemical properties of both metals and nonmetals.
Development of the Modern Periodic Table

20. Staircase
Left side is metals: Elements to the left of the semi-metal line on the periodic table are malleable (can be hammered into a shape), ductile (can be stretched into a wire) and good conductors of heat and electricity. These elements tend to lose electrons to form cations.
Right side is nonmetals: Elements to the right of the semi-metal line on the periodic table (and hydrogen) are brittle and insulators of heat and electricity. These elements tend to gain electrons to form anions or share electrons as bonds to form molecules.
On the steps is metaloids

22. The Modern Periodic Table
Development of the Modern Periodic Table

23. "The Elements"

24. Essential Questions How was the periodic table developed?
What are the key features of the periodic table?
Development of the Modern Periodic Table

25. Section 2
Classification of the Elements

26. The PT Song

27. Section 2: Classification of the Elements
Elements are organized into different blocks in the periodic table according to their electron configurations. K
What I Know W
What I Want to Find Out L
What I Learned

28. Organizing the Elements by Electron Configuration
Recall electrons in the highest principal energy level are called valence electrons. All group 1 elements have one valence electron.
Classification of the Elements

29. Organizing the Elements by Electron Configuration
Group 2 elements have two valence electrons. The number of valence electrons for elements in groups 13–18 is ten less than their group number. The energy level of an element’s valence electrons indicates the period on the periodic table in which it is found.
Classification of the Elements

30. The s-, p-, d-, and f-Block Elements
The shape of the periodic table becomes clear if it is divided into blocks representing the atom’s energy sublevel being filled with valence electrons.
Classification of the Elements

31. The s-, p-, d-, and f-Block Elements
s-block elements consist of group 1 and 2, and the element helium.
Group 1 elements have a partially filled s orbital with one electron.
Group 2 elements have a completely filled s orbital with two electrons.
Classification of the Elements

32. The s-, p-, d-, and f-Block Elements
Groups 13–18 fill the p orbitals. In group 18, both the s and p orbitals of the period’s principal energy level are completely filled.
Classification of the Elements

33. The s-, p-, d-, and f-Block Elements
The d-block contains the transition metals and is the largest block.
There are exceptions, but d-block elements usually have filled outermost s orbitals, and filled or partially filled d orbitals.
The five d orbitals can hold 10 electrons, so the d-block spans ten groups on the periodic table.
Classification of the Elements

34. The s-, p-, d-, and f-Block Elements
The f-block contains the inner transition metals.
f-block elements have filled or partially filled outermost s orbitals and filled or partially filled 4f and 5f orbitals.
The 7f orbitals hold 14 electrons, and the inner transition metals span 14 groups.
Classification of the Elements

35. Alkali Metals Element Symbol Hyperlink Lithium Li Sodium Na Potassium
Rubidium Rb
Cesium Cs
Francium Fr
Group 1A
Most reactive metals
Reactivity increases from the top to the bottom.
So reactive many are kept under oil to prevent reacting with water or oxygen.
One Valence Electron
Found in nature only in a compound.
Form +1 ions because they will easily give up 1 electron for stability.

36. Alkaline Earth Metals Element Symbol Hyperlink Beryllium Be Magnesium
Group 2A
Have 2 Valence Electrons
Harder than the metals in 1A.
Form +2 Ions because they easily give up 2 electrons for stability.
Magnesium used in photosynthesis within the chlorophyll.
Calcium used in teeth and bone.
Element
Symbol
Hyperlink
Beryllium Be
Magnesium Mg
Calcium Ca
Strontium Sr
Barium Ba
Radium Ra

37. Boron Family Element Symbol Hyperlink Boron B Aluminum Al Gallium Ga
Group 3A
Have 3 Valence electrons
Form +3 Ions because they easily give up 3 electrons for stability.
1 metalloid (Boron)
Six metals
Aluminum is the most abundant metal in the Earth’s crust.
People are encouraged to recycle aluminum because it doesn’t take that much energy to do so.
Element
Symbol
Hyperlink
Boron B
Aluminum Al
Gallium Ga
Indium In
Thallium Tl
Ununtrium
Uut

38. Carbon Family Element Symbol Hyperlink Carbon C Silicon Si Germanium
Group 4A
Have 4 Valence Electrons
Form +/- 4 Ions because it will easily lose or gain 4 electrons for stability.
1 Nonmetal (Carbon)
2 Metalloids
3 Metals
Metallic nature increases from top to bottom.
With the exception of water, most of the compounds in your body contain carbon.
Silicon is the second most abundant metal in the earth’s crust.
Element
Symbol
Hyperlink
Carbon C
Silicon Si
Germanium Ge
Tin Sn
Lead Pb
Ununquadium
Uuq

39. Nitrogen Family Group 5A Have 5 Valence Electrons
Forms -3 Ions because it will easily gain 3 electrons for stability.
2 nonmetals
2 metalloids
2 Metals
Nitrogen and Phosphorus are used in fertilizers.
Element
Symbol
Hyperlink
Nitrogen N
Phosphorus P
Arsenic As
Antimony Sb
Bismuth Bi
Ununpentium
Uup

40. Oxygen Family Element Symbol Hyperlink Oxygen O Sulfur S Selenium Se
Group 6A
Have 6 Valence Electrons
Forms -2 Ions because it will easily gain 2 electrons for stability.
3 nonmetals
2 metalloids
1 metal
Oxygen is the most abundant element in the Earth’s Crust.
Ozone is another from of oxygen. At ground level it can irritate your eyes and lungs. At higher levels it absorbs harmful radiation from the sun.
Element
Symbol
Hyperlink
Oxygen O
Sulfur S
Selenium Se
Tellurium Te
Polonium Po
Ununhexium
Uuh

41. Halogens Element Symbol Hyperlink Fluorine F Chlorine Cl Bromine Br
Group 7A
Have 7 Valence electrons
Form -1 Ions because it will easily gain 1 electron for stability.
Most reactive nonmetals increase from bottom to top.
Known as “Salt Formers”
5 nonmetals
1 Unknown
Fluorine is the most reactive.
React easily with most metals.
Element
Symbol Hyperlink
Fluorine F
Chlorine Cl
Bromine Br
Iodine I
Astatine At
Ununspetium
Uus

42. Noble Gases Element Symbol Hyperlink Helium He Neon Ne Argon Ar
Krypton Kr
Xenon Xe
Radon Rn
Ununoctium
Uuo
Group 8A
8 Valence Electrons
Helium is the exception with only 2 valence electrons.
Extremely Un-reactive (Do not form Ions)
Odorless and colorless.
Used in light bulbs.
All are used in neon lights except argon.
Have the most stable electron configuration.

43. Electron Configuration and the Periodic Table
SOLVE FOR THE UNKNOWN
For representative elements, the number of valence electrons can indicate the group number.
The s2 indicates the strontium’s valence electrons fill the s sublevel. Thus, strontium is in group 2 of the s-block.
The number of the highest energy level indicates the period number.
The 5 is 5s2 indicates that strontium is in period 5.
Use with Example Problem 1.
Problem
Strontium, which is used to produce red fireworks, has an electron configuration of [Kr]5s2. Without using the periodic table, determine the group, period, and block of strontium.
Response
ANALYZE THE PROBLEM
You are given the electron configuration of strontium.
EVALUATE THE ANSWER
The relationships between electron configuration and position on the periodic table have been correctly applied.
KNOWN
UNKNOWN
Electron configuration = [Kr]5s2
Group = ?
Period = ?
Block = ?
Classification of the Elements

44. Essential Questions
Why do elements in the same group have similar properties?
Based on their electron configurations, what are the four blocks of the periodic table?
Classification of the Elements

45. Section 3
Periodic Trends

46. Section 3: Periodic Trends
Trends among elements in the periodic table include their sizes and their abilities to lose or attract electrons. K
What I Know W
What I Want to Find Out L
What I Learned

47. Periodic Table Crash Course

48. Atomic Radius
Atomic size is a periodic trend influenced by electron configuration.
For metals, atomic radius is half the distance between adjacent nuclei in a crystal of the element.
Periodic Trends

49. Atomic Radius
For elements that occur as molecules, the atomic radius is half the distance between nuclei of identical atoms that are chemically bonded together.
Periodic Trends

50. Atomic Radius
Atomic radius generally decreases from left to right, caused by increasing positive charge in the nucleus.
Valence electrons are not shielded from the increasing nuclear charge because no additional electrons come between the nucleus and the valence electrons.
Atomic radius generally increases as you move down a group.
The outermost orbital size increases down a group, making the atom larger.
Periodic Trends

51. Atomic Radius
Periodic Trends

52. Interpret Trends in Atomic Radii
Use with Example Problem 2.
Problem
Which has the largest atomic radius: carbon (C), fluorine (F), beryllium (Be), or lithium (Li Explain your answer in terms of trends in atomic radii.
SOLVE FOR THE UNKNOWN
Determine the periods.
From the periodic table, all the elements are found to be in period 2.
Apply the trend of decreasing radii across a period.
Ordering the elements from left-to-right across the period yields: Li, Be, C, and F.
The first element in period 2, lithium, has the largest radius.
Response
ANALYZE THE PROBLEM
You are given four elements. First, determine the groups and periods the elements occupy. Then apply the general trends in atomic radii to determine which has the largest atomic radius.
EVALUATE THE ANSWER
The period trend in atomic radii has been correctly applied. Checking radii values in Figure 11 (slide 7) verifies the answer.
Periodic Trends

53. Ionic Radius
An ion is an atom or bonded group of atoms with a positive or negative charge.
When atoms lose electrons and form positively charged ions, they always become smaller for two reasons:
The loss of a valence electron can leave an empty outer orbital, resulting in a smaller radius.
Electrostatic repulsion decreases allowing the electrons to be pulled closer to the nucleus.
Periodic Trends

54. Ionic Radius
When atoms gain electrons, they can become larger, because the addition of an electron increases electrostatic repulsion.
Periodic Trends

55. Ionic Radius
The ionic radii of positive ions generally decrease from left to right.
The ionic radii of negative ions generally decrease from left to right, beginning with group 15 or 16.
Both positive and negative ions increase in size moving down a group.
Periodic Trends

56. Ionic Radius
Periodic Trends

57. Ionization Energy
Ionization energy is defined as the energy required to remove an electron from a gaseous atom.
The energy required to remove the first electron is called the first ionization energy.
Periodic Trends

58. Ionization Energy
Periodic Trends

59. Ionization Energy
Removing the second electron requires more energy, and is called the second ionization energy.
Each successive ionization requires more energy, but it is not a steady increase.
Periodic Trends

60. Ionization Energy
First ionization energy increases from left to right across a period.
First ionization energy decreases down a group because atomic size increases and less energy is required to remove an electron farther from the nucleus.
Periodic Trends

61. Ionization Energy
The ionization at which the large increase in energy occurs is related to the number of valence electrons.
The octet rule states that atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons.
The octet rule is useful for predicting what types of ions an element is likely to form.
Periodic Trends

62. Electronegativity
The electronegativity of an element indicates its relative ability to attract electrons in a chemical bond.
Electronegativity decreases down a group and increases left to right across a period.
Periodic Trends

63. Patterns on the Periodic Table
Atomic # L to R.
Atomic mass L to R.
Energy level and orbitals in rows from T to B.
(Physical Properties) metals metalloids nonmetals from L to R.
Columns atomic mass from T to B.
Columns are based on chemical properties (reactivity).
Valence Electrons from L to R.
Most reactive metals are on the left side.
Most reactive non-metals are on the right side.

65. Periodic Table Trends Rap

66. Essential Questions
What are the period and group trends of different properties?
How are period and group trends in atomic radii related to electron configuration?
Periodic Trends