the periodic table. ( very ) brief history 1869 mendeleev* & meyer published similar tables *...
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The Periodic Table
(very) Brief History• 1869 Mendeleev* & Meyer published similar
tables*First to be recognized at international convention
– Elements were ordered based on atomic mass
• Henry Moseley developed the atomic # concept– Proved more accurate than Mendeleev’s atomic mass
method
The Periodic Law
• When elements are arranged by increasing atomic # their chemical & physical properties show a periodic pattern.
Review of Element Symbol
• Atomic #– #protons
• Element Symbol• Atomic Mass
– Weighted average of all isotopes’ mass #
– Listed in AMUs– Equal to MM (g/mol)
• Element Name
54.938049 54.938049
Periodic Table Layout
• Groups or Families– Columns, Vertical– 18 groups
• Periods– Rows, Horizontal– 7 periods
• Kinds of Elements– Metals, Nonmetals, Semi-metals– Varying Properties
Groups to know– Group 1 - Alkali Metals– Group 2 - Alkaline Earth Metals– Group 17 Halogens– Group 18 - Noble Gases
Electron ConfigurationsUsing the Periodic Table
1IA
11
H1.00797
2IIA
23
Li6.939
4Be
9.0122
311
Na22.9898
12Mg
24.305
419K
39.102
20Ca
40.08
537
Rb85.47
38Sr
87.62
655
Cs132.905
56Ba
137.34
787Fr
[223]
88Ra[226]
s-block elements:
Group 1: Alkali
H - 1s1
Li - 1s22s1
Na- 1s22s22p63s1
K - 1s22s22p63s23p64s1
s-block elements:
Group 2: Alkaline Earth
Be - 1s22s2
Mg- 1s22s22p63s2
Ca - 1s22s22p63s23p64s2
Electron Configurations (con’t)
p-block elements:
Group 13: B -1s22s22p1
Group 14: Si -1s22s22p63s23p2
Group 15: As-1s22s22p63s23p64s23d104p3
Group 16: S -
1s22s22p63s23p4
Group 17: Br- 1s22s22p63s23p64s23d104p5
18VIIIA
13IIIA
14IVA
15VA
16VIA
17VIIA
2He
4.00265B
10.811
6C
12.0112
7N
14.0067
8O
15.9994
9F
18.9984
10Ne
20.17913Al
26.9815
14Si
28.086
15P
30.9738
16S
32.064
17Cl
35.453
18Ar
39.948
7
31Ga65.37
32Ge72.59
33As
74.9216
34Se78.96
35Br
79.909
36Kr
83.80
40
49In
114.82
50Sn
118.69
51Sb
121.75
52Te
127.60
53I
126.904
54Xe
131.30
59
81Tl
204.37
82Pb
207.19
83Bi
208.980
84Po[210]
85At
[210]
86Rn[222]
Noble Gas Configuration
Choose Noble Gas Prior to ElementFOCUS ON THE VALENCE SHELL
Put Noble gas in brackets,ex. [Ne]
This represents the “inner shell” of the element
Add the outer level electrons by row # (2-7) s & p
**d level starts on 4th row**4f & 5f start on 6th & 7th row
Examples:
Ni: [Ar] 4s23d8 **remember that 3d fills after 4s and before 4p
Sb: [Kr] 5s24d105p3
Trends in the Periodic TableDefinition: Predictable changes in properties of the elements as you move through the table. (Realize there are exceptions)
1 1H
2 3Li
4Be
3 11Na
12Mg
4 19K
20Ca
5 37Rb
38Sr
6 55Cs
56Ba
7 87Fr
88Ra
21Sc
22Ti
23V
24Cr
25Mn
26Fe
27Co
28Ni
29Cu
30Zn
39Y
40Zr
41Nb
42Mo
43Tc
44Ru
45Rh
46Pd
47Ag
48Cd
57La
72Hf
73Ta
74W
75Re
76Os
77Ir
78Pt
79Au
80Hg
89Ac
104Rf
105 106 107 108 109
2He
5B
6C
7N
8O
9F
10Ne
13Al
14Si
15P
16S
17Cl
18Ar
31Ga
32Ge
33As
34Se
35Br
36Kr
49In
50Sn
51Sb
52Te
53I
54Xe
81Tl
82Pb
83Bi
84Po
85At
86Rn
Db Hs MtSg Bh
Ionic Size+Ions are Smaller
- Ions are larger
Atomic Radii Decrease
Incr
eas
e
Ionization EnergyIncrease
Dec
reas
e
Atomic Radii - distance from the nucleus to outermost electron.
Ionization Energy - energy required to remove an electron (kJ/mol)
Electron Affinity – energy change when neutral atom gains electron
Electron AffinityIncrease
Dec
reas
e
Ionization Energy• In general, ionization energies of the main-group
elements increase across each period.
• This increase is caused by increasing nuclear charge.
• A higher charge more strongly attracts electrons in the same energy level.
• Among the main-group elements, ionization energies generally decrease down the groups.
• Electrons removed from atoms of each succeeding element in a group are in higher energy levels, farther from the nucleus.(electron shielding)
• The electrons are removed more easily.
Additional Trend Information
Electron AffinityThe energy associated with an atom gaining or losing an
electron. (kJ/mol)• + Energy means it requires energy …not favorable
• - Energy means it gives up energy…favorable
• ElectronegativityThe ability to attract an electron during bonding
• Increases up a group and across a period
Electron Affinity
• The energy change that occurs when an electron is acquired by a neutral atom is called the atom’s electron affinity.
• Electron affinity generally increases across periods.• Increasing nuclear charge along the same
sublevel attracts electrons more strongly
• Electron affinity generally decreases down groups.• The larger an atom’s electron cloud is, the farther
away its outer electrons are from its nucleus.
Ionic Radii• A positive ion is known as a cation.
• The formation of a cation by the loss of one or more electrons always leads to a decrease in atomic radius.
• The electron cloud becomes smaller. • The remaining electrons are drawn closer to the nucleus by its
unbalanced positive charge.
• A negative ion is known as an anion.
• The formation of an anion by the addition of one or more electrons always leads to an increase in atomic radius.
Ionic Radii, continued• Cationic and anionic radii decrease across a period.
• The electron cloud shrinks due to the increasing nuclear charge acting on the electrons in the same main energy level.
• The outer electrons in both cations and anions are in higher energy levels as one reads down a group.
• There is a gradual increase of ionic radii down a group.
Electronegativity• Valence electrons hold atoms together in chemical
compounds.
• In many compounds, the negative charge of the valence electrons is concentrated closer to one atom than to another.
• Electronegativity is a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound.
• Electronegativities tend to increase across periods, and decrease or remain about the same down a group.
The Periodic Table
(very) Brief History
• 1800’s - Dobereiner introduced “Triads”– 3 elements with similar properties
• 1865 - Newlands introduced “Law of Octaves”– At this time 62 known elements– 1st behaved like 8th, 2nd like 9th…
• 1869 Mendeleev* & Meyer published similar tables*First to be recognized at international convention
– Elements were ordered based on atomic mass
The Periodic Law
• When elements are arranged by increasing atomic # their chemical & physical properties show a periodic pattern.
1913 - Henry Moseley developed the atomic # concept.– Proved more accurate than Mendeleev’s atomic mass method
Review of Element Symbol
• Atomic #– #protons
• Element Symbol• Atomic Mass
– Weighted average of all isotopes’ mass #
– Listed in AMUs
– Equal to MM (g/mol)
• Element Name
54.938049
Periodic Table Layout• Groups or Families
– Columns, Vertical
– 18 groups
• Periods– Rows, Horizontal
– 7 periods
• Kinds of Elements– Metals, Nonmetals, Semi-metals
– Varying Properties
Groups to know– Group 1 - Alkali Metals– Group 2 - Alkaline Earth Metals– Group 17 Halogens– Group 18 - Noble Gases
Electron ConfigurationsUsing the Periodic Table
1IA
11
H1.00797
2IIA
23
Li6.939
4Be
9.0122
311
Na22.9898
12Mg24.305
419K
39.102
20Ca40.08
537
Rb85.47
38Sr
87.62
655
Cs132.905
56Ba
137.34
787Fr[223]
88Ra[226]
s-block elements:
Group 1: Alkali
H - 1s1
Li - 1s22s1
Na- 1s22s22p63s1
K - 1s22s22p63s23p64s1
s-block elements:
Group 2: Alkaline Earth
Be - 1s22s2
Mg- 1s22s22p63s2
Ca - 1s22s22p63s23p64s2
Electron Configurations (con’t)
p-block elements:
Group 13: B -1s22s22p1
Group 14: Si -1s22s22p63s23p2
Group 15: As-1s22s22p63s23p64s23d104p3
Group 16: S -
1s22s22p63s23p4
Group 17: Br-
1s22s22p63s23p64s23d104p5
18VIIIA
13IIIA
14IVA
15VA
16VIA
17VIIA
2He
4.00265B
10.811
6C
12.0112
7N
14.0067
8O
15.9994
9F
18.9984
10Ne
20.179
13Al
26.9815
14Si
28.086
15P
30.9738
16S
32.064
17Cl
35.453
18Ar
39.948
7
31Ga65.37
32Ge72.59
33As
74.9216
34Se78.96
35Br
79.909
36Kr83.80
40
49In
114.82
50Sn
118.69
51Sb
121.75
52Te
127.60
53I
126.904
54Xe
131.30
59
81Tl
204.37
82Pb
207.19
83Bi
208.980
84Po[210]
85At[210]
86Rn[222]
Noble Gas Configuration
Choose Noble Gas Prior to ElementFOCUS ON THE VALENCE SHELL
Put Noble gas in brackets,ex. [Ne]
This represents the “inner shell” of the element
Add the outer level electrons by row # (2-7) s & p
**d level starts on 4th row**4f & 5f start on 6th & 7th row
Examples:
Ni: [Ar] 4s23d8 **remember that 3d fills after 4s and before 4p
Sb: [Kr] 5s24d105p3
Trends in the Periodic TableDefinition: Predictable changes in properties of the elements as you move through the table.
1 1H
2 3Li
4Be
3 11Na
12Mg
4 19K
20Ca
5 37Rb
38Sr
6 55Cs
56Ba
7 87Fr
88Ra
21Sc
22Ti
23V
24Cr
25Mn
26Fe
27Co
28Ni
29Cu
30Zn
39Y
40Zr
41Nb
42Mo
43Tc
44Ru
45Rh
46Pd
47Ag
48Cd
57La
72Hf
73Ta
74W
75Re
76Os
77Ir
78Pt
79Au
80Hg
89Ac
104Rf
105 106 107 108 109
2He
5B
6C
7N
8O
9F
10Ne
13Al
14Si
15P
16S
17Cl
18Ar
31Ga
32Ge
33As
34Se
35Br
36Kr
49In
50Sn
51Sb
52Te
53I
54Xe
81Tl
82Pb
83Bi
84Po
85At
86Rn
Db Hs MtSg Bh
Ionic Size
+Ions are Smaller
- Ions are larger
Atomic Radii Decrease
Incr
ease
Ionization EnergyIncrease
Dec
reas
e
Atomic Radii - distance from the nucleus to outermost electron.
Ionization Energy - energy required to remove an electron (kJ/mol)
Additional Trend Information
Electron AffinityThe energy associated with an atom gaining or losing an
electron. (kJ/mol)• + Energy means it requires energy …not favorable
• - Energy means it gives up energy…favorable
• ElectronegativityThe ability to attract an electron during bonding
• Increases up a group and across a period