1. Mr. Matthew Totaro Legacy High School Honors Chemistry
The Periodic Table
Mr. Matthew Totaro
Legacy High School
Honors Chemistry

2. Döbereiner’s Triads Name Atomic Mass Calcium 40 Barium 137
Johann Döbereiner
~1817
Name
Atomic
Mass
Calcium
Barium
Average
Strontium
Chlorine
Iodine
Average
Bromine
Sulfur
Tellurium
Average
Selenium
Döbereiner found that the properties of the metals calcium, barium, and strontium were very similar.
He also noted that the atomic mass of strontium was about midway between those of calcium and barium.
Döbereiner discovered groups of three related elements which he termed a triad.
Döbereiner discovered groups of three related elements which he termed a triad.

3. Newlands Law of Octaves
John Newlands
~1863
Newlands Law of Octaves 1 Li Na K 2 Be Mg 3 B Al 4 C Si 5 N P 6 O S 7 F Cl
John Newlands, suggested another classification. He arranged the elements in order of their increasing atomic masses. He noted that there appeared to be a repetition of similar properties for every eighth element. Therefore, he arranged the elements known at that time into seven groups of seven each. [Noble gases were not known at the time]. Newland’s referred to his arrangement as the law of octaves.
Newland’s law of octaves was proposed to explain the properties which occurred with every eighth element when the elements were arranged in order of increasing atomic mass.

4. Dmitri Mendeleev Ordered elements by atomic mass.
Saw a repeating pattern of properties.
Periodic law —When the elements are arranged in order of increasing relative mass, certain sets of properties recur periodically.
Used pattern to predict properties of undiscovered elements.
Where atomic mass order did not fit other properties, he reordered by other properties.
Te & I

5. Mendeleev’s Periodic Table

6. Mendeleev's Predictions

7. Periodicity Periodic = repeating
When one looks at the properties of elements, one notices a repeating pattern of characteristics & reactivities.
Periodic = repeating

8. Periodicity
= Metal
= Metalloid
= Nonmetal

9. Metals Solids at room temperature, except Hg.
Reflective surface = Luster.
Shiny
Conduct heat.
Conduct electricity.
Malleable.
Can be shaped.
Ductile.
Drawn or pulled into wires.
About 75% of the elements are metals.
Lower left on the table.

10. Nonmetals Found in all 3 states. Poor conductors of heat.
Poor conductors of electricity.
Solids are brittle.
Upper right on the table.
Except H.
Nonmetallic
Bromine

11. Properties of Silicon:
Metalloids
Show some properties of metals and some of nonmetals.
Also known as semiconductors.
Properties of Silicon:
Shiny
Conducts electricity
Does not conduct heat well
Brittle

12. The Modern Periodic Table
Determined the atomic numbers of elements from their X-ray spectra (1914)
Arranged elements by increasing atomic number
Killed in WW I at age 28
(Battle of Gallipoli in Turkey)
H.G.J. Moseley ( ) while doing post-doctoral work (with Ernest Rutherford) bombarded X-rays at atoms in increasing number and noted that the nuclear charge increased by 1 for each element. This gave him the idea to organize the elements by increasing atomic number.
Periodic law – elements organized by increasing atomic number on periodic table (1913)
In 1913, Moseley analyzed the frequencies of X -rays emitted by the elements and discovered that the underlying foundation of the order of the elements was atomic number, not atomic mass.
Moseley hypothesized that the placement of each element in his series corresponded to its atomic number Z, which is the number of positive charges (protons) in its nucleus.
Moseley- wavelengths in X-rays determined by the number of protons in the nucleus of the anode atoms
- change anode, change wavelength
Henry Moseley

13. The Modern Periodic Table
Elements are arranged from left to right in order of increasing atomic number
There are 18 vertical columns called Families
There are 7 horizontal rows called Periods.

14. The Modern Periodic Table

15. Long Form of the Periodic Table

16. The Modern Periodic Table
Main group = representative elements = “A” groups
Transition elements = “B” groups
all metals
Bottom rows = inner transition elements = rare earth elements
metals
really belong in Period 6 & 7

17. find table that includes rare earth elements

19. Families of the Elements

20. = Alkali metals = Alkali earth metals = Noble gases = Halogens
= Lanthanides
= Actinides
= Transition metals
add pictures of elements from text

21. Important Groups – Alkali Metals
Group IA (1)= Alkali Metals
Hydrogen usually placed here, though it doesn’t really belong
Soft, low melting points, low density
Flame tests: Li = red, Na = yellow, K = violet
Very reactive, never find uncombined in nature
lithium
sodium
potassium
rubidium
cesium

22. Important Groups - Alkali Earth Metals
magnesium
calcium
beryllium
strontium
barium
Group IIA (2)= Alkali Earth Metals
harder, higher melting, and denser than alkali metals
Mg alloys used as structural materials
flame tests: Ca = red, Sr = red, Ba = yellow-green
reactive, but less than corresponding alkali metal

23. Important Groups – Halogens
Group VIIA (17) = halogens
Nonmetals
Only family with solids, liquids, and gases
All diatomic
Very reactive
fluorine
chlorine
bromine
iodine
astatine

24. Important Groups - Noble Gases
helium
neon
argon
krypton
xenon
Group VIIIA (18) = Noble Gases
all gases at room temperature
very low melting and boiling points
very unreactive, practically inert
very hard to remove electron from or give an electron to

25. Important Groups - Hydrogen
Nonmetal
Colorless, diatomic gas
very low melting point and density
Makes up over 90% of all atoms in the universe
Excited Hydrogen Gas

26. States of the Elements (at STP)
Orange = Solid Red = Liquid Purple = Gas

27. The Modern Periodic Table

28. Valence Electrons
The electrons in all the sublevels with the highest principal energy levels are called the valence electrons.
Electrons in lower energy levels are called core electrons.
Chemists have observed that one of the most important factors in the way an atom behaves, both chemically and physically, is the number of valence electrons.

29. Valence Electrons and Core Electrons

30. Valence vs. Core Electrons in Carbon
4 Valence Electrons
C = 6 e- =1s22s22p2

31. Valence Electrons, Continued
Rb = 37 electrons = 1s22s22p63s23p64s23d104p65s1
The highest principal energy level of Rb that contains electrons is the 5th, therefore, Rb has 1 valence electron and 36 core electrons.
Kr = 36 electrons = 1s22s22p63s23p64s23d104p6
The highest principal energy level of Kr that contains electrons is the 4th, therefore, Kr has 8 valence electrons and 28 core electrons.

32. Electron Configuration from the Periodic Table1 2 3 4 5 6 7 2A 3A 4A 5A 6A 7A Ne
3s2 P
3p3
P = [Ne]3s23p3
P has 5 valence electrons.

33. Practice—Determine the Number of Valence Electrons in an Arsenic, As, Atom (use the Noble Gas shortcut).

34. Electron Configuration from the Periodic Table, Continued1 2 3 4 5 6 7 2A 3A 4A 5A 6A 7A
3d10 Ar As
4s2
4p3
As = [Ar] 3d104s24p3
As has 5 valence electrons.

35. 6s 6p 6d 7s 5s 5p 5d 5f 4s 4p 4d 4f 3s 3p 3d
Energy 2s 2p 1s

36. Sublevels and the Periodic Table
p1 p2 p3 p4 p5 s2 1 2 3 4 5 6 7 p6
d1 d2 d3 d4 d5 d6 d7 d8 d9 d10
f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14

38. Element Blocks on the Periodic Table
Blocks of Elements
This diagram classifies elements into blocks according to sublevels that are filled or filling with electrons. Interpreting Diagrams In the highest occupied energy level of a halogen atom, how many electrons are in the p sublevel?

39. Electron Configuration and the Periodic Table
Elements in the same column have similar chemical and physical properties because they have the same number of valence electrons.
The number of valence electrons for the main group elements is the same as the group number.

40. Electron Configuration of The Alkali Metals

41. Electron Configuration of The Halogens41

42. Electron Configuration of The Noble Gases

43. Periodic Trends in the Properties of the Elements

44. Reactivity
For the metals, as you move down a family, reactivity goes up. As you move across a period, reactivity goes down.
Brainiac’s Video
For the nonmetals, as you move down a family, reactivity goes down. As you move across a period, reactivity goes up.
Except for the Noble Gases!!!!

45. Trends in Atomic Size Either volume or radius.
Treat atom as a hard marble.
As you traverse down a column on the periodic table, the size of the atom increases.
Valence shell farther from nucleus.
Effective nuclear charge fairly close.
As you traverse left to right across a period, the size of the atom decreases.
Adding electrons to same valence shell.
Effective nuclear charge increases.
Valence shell held closer.

46. Trends in Atomic Size, Continued

47. Be (4p+ and 4e-) Mg (12p+ and 12e-) Ca (20p+ and 20e-) Group IIA 2e-

48. Li (3p+ and 3e-) Be (4p+ and 4e-) B (5p+ and 5e-) C (6p+ and 6e-)
Period 2
2e-
1e-
3 p+
2e-
4 p+
2e-
3e-
5 p+
Li (3p+ and 3e-)
Be (4p+ and 4e-)
B (5p+ and 5e-)
6 p+
2e-
4e-
8 p+
2e-
6e-
10 p+
2e-
8e-
C (6p+ and 6e-)
O (8p+ and 8e-)
Ne (10p+ and 10e-)

49. Choose the Larger Atom in Each Pair
C or O
Li or K
C or Al
Se or I

50. Choose the Larger Atom in Each Pair
C or O
Li or K
C or Al
Se or I?

51. Practice—Choose the Larger Atom in Each Pair.
1. N or F
2. C or Ge
3. N or Al
4. Al or Ge

52. Practice—Choose the Larger Atom in Each Pair, Continued.
N or F, N is further left
N or F
C or Ge
N or Al, Al is further down & left
N or F
C or Ge, Ge is further down
N or F
C or Ge
N or Al
Al or Ge? opposing trends

53. Trends in Ionic Radius Ions in same group have same charge
Ion size increases down the column
higher valence level, larger size
Cations smaller than neutral atoms; anions larger than neutral atoms
Cations smaller than anions
Larger positive charge = smaller cation
Larger negative charge = larger anion

56. Example: Choose the larger of each pair
S or S2−
Ca or Ca2+
Br− or Kr

57. Ionization Energy
Minimum energy needed to remove an electron from an atom.
Gas state.
Valence electrons are the easiest to remove.
M(g) + 1st IE  M1+(g) + 1 e-
M+1(g) + 2nd IE  M2+(g) + 1 e-
First ionization energy = energy to remove electron from neutral atom; 2nd IE = energy to remove from +1 ion; etc.

58. Trends in Ionization Energy
As you move down a family, the IE gets smaller.
Valence electron farther from nucleus.
As you move left to right across a period, the IE gets larger.

59. Trends in Ionization Energy, Continued

60. Example—Choose the Atom in Each Pair with the Higher First Ionization Energy
Al or S
As or Sb, As is farther up
1. Al or S
2. As or Sb
3. N or Si
4. O or Cl, opposing trends
Al or S
As or Sb
N or Si, N is further up and right
Al or S, S is further Right

61. Practice—Choose the Atom with the Highest Ionization Energy in Each Pair
1. Mg or P
2. Cl or Br
3. Se or Sb
4. P or Se

62. Practice—Choose the Atom with the Highest Ionization Energy in Each Pair, Continued
1. Mg or P
2. Cl or Br
3. Se or Sb
4. P or Se ?

63. Metallic Character
How well an element’s properties match the general properties of a metal.
In general, metals are found on the left of the periodic table and nonmetals on the right.
As you go left to right across the period, the elements become less metallic.
As you go down a column, the elements become more metallic

65. Example—Choose the More Metallic Element in Each Pair
Sn or Te, Sn is further left
Sn or Te
P or Sb
Ge or In
S or Br? opposing trends
Sn or Te
P or Sb
Ge or In, In is further down & left
Sn or Te
P or Sb, Sb is further down

66. Practice—Choose the More Metallic Element in Each Pair
Na or Al
Si or Sn
Br or Te
Se or I

67. Practice—Choose the More Metallic Element in Each Pair, Continued
Na or Al
Si or Sn
Br or Te
Se or I ?

68. Electronegativity
The ability of an atom to attract valence electrons to itself is called electronegativity
Increases across period (left to right) and
Decreases down group (top to bottom)
fluorine is the most electronegative element
francium is the least electronegative element
noble gas atoms are not assigned values
opposite of atomic size trend

69. Electronegativity Scale