Download atomic mass

History of Chemistry
Early models of the atom
• Democritus- early Greek philosopher
• matter made up of tiny indivisible particles
called atoms
•
Dalton- “1st modern atomic theory”
5 Parts to theory
1) All elements made of tiny particles called atoms.
2) Atoms of same element are identical;
3)different atom = different element
4) Atoms bind together in simple whole number ratios.
H2O 2:1 correct
H1.25O 1.25:1 incorrect
(2:1 ratio) 2 H + O  H2O
(2:2 ratio) 2 H + 2 O  H2O2
5)Chemical reactions join or rearrange atoms
But atoms can not change into another element
Structure of Atom:
J.J. Thomson- Plum Pudding Model
Or chocolate chip cookie
Electron- J.J. Thomson used cathode ray tube
to discover electrons, e- have a negative charge
Structure of Atom:
Proton- positively charged subatomic particle
Goldstein- P+ mass 1840 times larger than e- mass
Neutron- neutral charged subatomic particle
- Discovered by Chadwick
- Mass of proton = mass of neutron
Rutherford- discovered atoms have a nucleus that e- orbit
Rutherford Performed Gold Foil Experiment
Shot alpha particles (+ charge) from radioactive lead
through gold foil
He expected it to go through b/c heavy mass and fast
But Some bounced back
Concluded it had a dense center called it nucleus
Nucleus is most dense has protons & neutrons
Almost all atoms mass located in nucleus
Mendeleev
• Created the first periodic table
• Observed when elements are arranged in order of
increasing atomic mass then chemical and physical
properties appear at regular intervals
Based on atomic mass
Based on atomic number
•
The Periodic Table
Mendeleev- Arranged by increasing atomic
mass, left blank spaces, able to predict properties
of missing elements b/c properties repeated
• Moseley- arranged in order of increasing atomic
number, the one we use today
Periodic Law- elements in increasing atomic
number will have a periodic repetition of physical &
chemical properties
Atoms
Atomic Number- # protons in nucleus
Atoms are electrically neutral so
#p = #e
Protons = electrons
Atoms
Mass Number = #p + #n = mass #
number of protons + number of neutrons = mass number
If given Mass # and proton # you can figure out #of neutrons
Mass # - #p = #n
Atoms
• Shorthand:
Mass #
Symbol
# Protons
1
H
1
4
He
2
figure out for Carbon
Atoms
12
C
6
Atoms
• Isotope- same # p, different # n; so
different mass
1
2
H
1
H
1
3
H
1
• Problems:
– Fill in the chart:
Element
Mass
#
Be
9
Atomic
#
#
#
#
Protons Electrons Neutrons
4
20
Na
23
10
11
15
16
• Problems:
– Fill in the chart:
Element
Mass
#
Atomic
#
#
#
#
Protons Electrons Neutrons
Be
9
4
4
4
5
Ne
20
10
10
10
10
Na
23
11
11
11
12
P
31
15
15
15
16
• Warm up Problems:
– Fill in the chart:
Element
Mass
#
Mg
24
Atomic
#
#
#
#
Protons Electrons Neutrons
12
32
K
39
16
19
32
41
• Warm up Answer:
– Fill in the chart:
Element
Mass
#
Atomic
#
#
#
#
Protons Electrons Neutrons
Mg
24
12
12
12
12
S
32
16
16
16
16
K
39
19
19
19
20
Ge
73
32
32
32
41
3 Main Groups of Elements on PT (Periodic Table)
MetalsNon-Metals
Metalloids
1
IA
1
18
VIIIA
2
IIA
13
IIIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
14
IVA
15
VA
16
VIA
17
VIIA
3 Main Groups of Elements on PT (Periodic Table)
Metalso
Left side of PT
o
80% elements
o
Conduct electricity
o
Luster
o
Ductile
o
Malleable
o
Mostly solids w/ some exceptions
o
1A Alkali metals
o
2A Alkaline Earth Metals
o Group B- Transition & Inner Transition Metals
1
IA
1
2
IIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
Metals
11
IB
12
IIB
18
VIIIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA

o
o
o
o
o
o
o
NonmetalsRight side of PT
Don’t conduct electricity
Aren’t ductile or malleable
Can be solids, liquids or gases
No luster
7A- Halogens
0- Noble gases
1
IA
1
18
VIIIA
2
IIA
13
IIIA
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
4
5
6
Metalloidso
Border Stair Step
o
Properties of metals & nonmetals
o
Used in solar cells & computer chips
7
10
11
IB
12
IIB
14
IVA
15
VA
16
VIA
17
VIIA
THE PERIODIC TABLE
• The rows across the elements in the
periodic table are called periods 1-7
• The columns down are called groups.
• groups numbered 1 to 18 or 1A-8A
1
1
IA
1
H
Periodic Table
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA
1.00797
2
3
3
4
Li
Be
6.939
9.0122
11
Na
12
Mg
5
B
5
6
19
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
Ca
Sc
Ti
22
23
39.102
40.08
44.956
47.90
50.942
37
Rb
38
Sr
39
Y
40
Zr
41
Nb
Mo
Tc
85.47
87.62
88.905
91.22
92.906
95.94
[99]
55
56
57
72
73
74
75
Ba
21
La
132.905 137.34 138.91
7
87
88
8
O
9
F
8
9
VIIIB
10
11
IB
12
IIB
13
Al
14
Si
15
P
16
S
17
Cl
26.9815 28.086 30.9738 32.064 35.453
K
Cs
20
7
N
He
4.0026
10
Ne
10.811 12.0112 14.0067 15.9994 18.9984 20.179
22.9898 24.305
4
6
C
18
VIIIA
2
89
Hf
V
Ta
24
Cr
104
Ra
Ac
Ku
[223]
[226]
[227]
[260]
105
26
Fe
27
Co
51.996 54.9380 55.847 58.9332
42
W
178.49 180.948 183.85
Fr
25
Mn
106
43
44
Ru
45
Rh
101.07 102.905
76
77
Re
Os
Ir
186.2
190.2
192.2
107
108
109
28
29
30
31
32
33
Ni
Cu
Zn
Ga
Ge
58.71
63.54
65.37
65.37
72.59 74.9216
46
47
48
49
Pd
Ag
Cd
In
106.4 107.870 112.40 114.82
78
Pt
79
Au
80
Hg
81
Tl
195.09 196.967 200.59 204.37
50
Sn
As
51
Sb
118.69 121.75
82
Pb
83
Bi
207.19 208.980
34
35
18
Ar
39.948
36
Se
Br
Kr
78.96
79.909
83.80
52
53
Te
I
54
Xe
127.60 126.904 131.30
84
85
86
Po
At
Rn
[210]
[210]
[222]
GROUPS or Families
• Group 1(1A) are found on the far left side
and are called the alkali metals
• Group 2(2A) are found on the far left side
and are called the alkaline metals
• Group 7A(17) are found at the right hand
side and are called the halogens.
• Group 8A(18) are called the noble gases
GROUP 7- halogens
are all non- metals
they are:-Fluorine,Chlorine,Bromine,Iodine
• They have low melting points (this means
that the change from a solid to a liquid at a
low temperature)
• They do not conduct electricity
• They go around as pairs of atoms.
• We call them diatomic molecules
• We write them like this
• Fluorine - F2
• Chlorine - Cl2
• Bromine - Br2
• Iodine
- I2
What are they like?
•
•
•
•
Fluorine is a very pale yellow gas
Chlorine is a green gas
Bromine is a dark red brown liquid
Iodine is a black shiny solid
THE REACTIONS OF THE
HALOGENS
• The halogens like to take
•The
like reactions
to take
parthalogens
in chemical
part in chemical reactions
• The react with metals to
•The react with metals to
make salts
make salts
••The
Themost
mostreactive
reactivehalogen
is fluorine
and
is halogen
fluorine and
the least
the least
reactive is
reactive
is iodine.
iodine.
•They
get less reactive
•as They
getdown
less the
reactive
you go
groupas
you go down the group
most
reactive
Least
reactive
Uses of the halogens
• Iodine is used as an antiseptic
• Chlorine is used in swimming pools to
kill bacteria
• Fluorine is used in tooth paste
• Bromine is used photographic film
How much does an atom weigh?
• Amu- (atomic mass unit) = 1/12 C-12 atom
• How many protons in C?
• How many neutrons in C?
• Atomic Mass of C?
• Amu- (atomic mass unit) = 1/12 C-12 atom
• How many protons in C = 6
• How many neutrons in C = 6
• Atomic Mass of C =12
• Therefore 1/12th of a C atom is =
• to 1 proton
• Or = to 1 neutron
Relative Atomic Mass
1 p = 1 amu
1 n = 1 amu
1 e- = 0 amu
Therefore one carbon atom
weighs 12 amu’s
© Addison-Wesley Publishing Company, Inc.
Isotopes- same # protons different # neutrons
6
3
7
3
Li
0.00000 amu
Li
6
3
7
3
Li
lithium - 6
0.00000 amu
lithium - 7
Li
Li-6 = 6.0 amu
6.0 amu
Li-7 = 7.0 amu
7.0 amu
Isotopes
Carbon-12 vs. Carbon-14
© Addison-Wesley Publishing Company, Inc.
Isotopes
• Chlorine-37
– atomic #:
17
– mass #:
37
– # of protons:
17
– # of electrons:
17
– # of neutrons:
20
37
17
Cl
Mass #
• mass # = protons + neutrons
• always a whole number
• NOT on Periodic Table!
• Nuclear symbol:
Mass #
Atomic #
12
6
C
Average Atomic Mass
• weighted average of all isotopes
• on the Periodic Table
• round to 2 decimal places
• Average atomic mass- is mass on PT
-Based on natural abundance of isotopes
1.
Change % to decimal
2.
Multiply decimal by the mass
3.
Add the numbers together
• Average atomic mass- is mass on PT
-Based on natural abundance of isotopes
1)Change % to decimal
2)Multiply decimal by the mass
3)Add the numbers together
Element X has two isotopes. The isotope
with a mass of 10.012 amu has a relative
abundance of 19.91%. The isotope with a
mass of 11.009 amu has a relative abundance
of 80.09%. Calculate the atomic mass of
this element.
•
Average atomic mass- is mass on PT
-Based on natural abundance of isotopes
1)Change % to decimal .1991 and .8009
2)Multiply decimal by the mass
3)Add the numbers together
Element X has two isotopes. The isotope with a
mass of 10.012 amu has a relative abundance of
19.91%. The isotope with a mass of 11.009 amu
has a relative abundance of 80.09%. Calculate the
atomic mass of this element.
•
Average atomic mass- is mass on PT
-Based on natural abundance of isotopes
1)Change % to decimal .1991 and .8009
2)Multiply decimal by the mass .1991x10.012 = 1.993
.8009 x 11.009=8.817
3)Add the numbers together
Element X has two isotopes. The isotope with a
mass of 10.012 amu has a relative abundance of
19.91%. The isotope with a mass of 11.009 amu
has a relative abundance of 80.09%. Calculate the
atomic mass of this element.
•
Average atomic mass- is mass on PT
-Based on natural abundance of isotopes
1)Change % to decimal .1991 and .8009
2)Multiply decimal by the mass .1991x10.012 = 1.993
.8009 x 11.009=8.817
3)Add the numbers together 10.810 amu
Element X has two isotopes. The isotope with a
mass of 10.012 amu has a relative abundance of
19.91%. The isotope with a mass of 11.009 amu
has a relative abundance of 80.09%. Calculate the
atomic mass of this element.
Average atomic mass [Worksheet]
• Based on abundance of isotopes
1)Change % to decimal
2)Multiply decimal by the mass
3)Add the numbers together
50.54% of naturally occurring isotopes of bromine
have an atomic mass of 78.92 amu. While the
other 49.46% of isotopes of bromine have an
atomic mass of 80.92amu. Calculate the average
atomic mass of bromine.
Average atomic mass
• Based on abundance of isotopes
1)Change % to decimal .5054 and .4946
2)Multiply decimal by the mass
3)Add the numbers together
50.54% of naturally occurring isotopes of bromine
have an atomic mass of 78.92 amu. While the
other 49.46% of isotopes of bromine have an
atomic mass of 80.92amu. Calculate the average
atomic mass of bromine.
Average atomic mass
• Based on abundance of isotopes
1)Change % to decimal .5054 and .4946
2)Multiply decimal by the mass .5054x78.92= 39.89
.4946 x 80.92= 40.02
3)Add the numbers together
50.54% of naturally occurring isotopes of bromine
have an atomic mass of 78.92 amu. While the
other 49.46% of isotopes of bromine have an
atomic mass of 80.92amu. Calculate the average
atomic mass of bromine.
Average atomic mass
• Based on abundance of isotopes
1)Change % to decimal .5054 and .4946
2)Multiply decimal by the mass .5054x78.92= 39.89
.4946 x 80.92= 40.02
3)Add the numbers together 39.89 + 40.02 = 79.91
50.54% of naturally occurring isotopes of bromine
have an atomic mass of 78.92 amu. While the
other 49.46% of isotopes of bromine have an
atomic mass of 80.92amu. Calculate the average
atomic mass of bromine.
Average Atomic Mass
• Calculate avg. atomic mass of oxygen if
abundance is 99.76% 16O, 0.04% 17O, and
0.20% 18O.
.9976 x 16 = 15.96
.0004 x 17 = 0.00068
16.00
.002 x 18 = 0.036
amu
16.00
Average Atomic Mass
• EX: Find chlorine’s average atomic mass if
approximately 8 of every 10 atoms are chlorine35 and 2 are chlorine-37.
•
•
•
•
8/10 = .80
2/10 = .20
.80 x 35 = 28.0
.2 x 37 = 7.4
35.4
35.40 amu
• Warm up Answer:
– Fill in the chart:
Element
Mass
#
Atomic
#
#
#
#
Protons Electrons Neutrons
Mg
24
12
12
12
12
S
32
16
16
16
16
K
39
19
19
19
20
Ge
73
32
32
32
41
Dmitri Mendeleev (1869)
In 1869 Mendeleev and Lothar Meyer (Germany)
published nearly identical classification schemes
for elements known to date. The periodic table is
base on the similarity of properties and reactivities
exhibited by certain elements. Later, Henri
Moseley ( England,1887-1915) established that
each elements has a unique atomic number, which
is how the current periodic table is organized.
http://www.chem.msu.su/eng/misc/mendeleev/welcome.html
The Periodic Table
• A map of the building block of matter.
1
1
IA
1
H
Periodic Table
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA
1.00797
2
3
Li
4
5
Be
B
6.939 9.0122
3
11
Na
12
Mg
19
K
20
Ca
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
6
37
38
21
Sc
22
Ti
23
V
24
Cr
25
Mn
39
43
Sr
Mo
Tc
[99]
56
57
La
72
Hf
Nb
42
87.62 88.905 91.22 92.906 95.94
Ba
Zr
41
Rb
55
Y
40
85.47
Cs
73
Ta
74
W
75
Re
132.905 137.34 138.91 178.49 180.948 183.85 186.2
7
87
88
8
O
9
F
4.0026
10
Ne
11
IB
12
IIB
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
26.9815 28.086 30.9738 32.064 35.453 39.948
26
Fe
27
Co
28
Ni
39.102 40.08 44.956 47.90 50.942 51.996 54.9380 55.847 58.9332 58.71
5
7
N
He
10.811 12.0112 14.0067 15.9994 18.9984 20.179
22.9898 24.305
4
6
C
18
VIIIA
2
89
104
Fr
Ra
Ac
Ku
[223]
[226]
[227]
[260]
105
106
107
44
Ru
45
Rh
46
Pd
29
30
31
32
33
Ge
63.54
65.37
65.37
72.59 74.9216 78.96 79.909 83.80
47
48
49
Ag
Cd
In
Sn
Sb
52
Te
Br
36
Ga
51
Se
35
Zn
50
As
34
Cu
53
I
Kr
54
Xe
101.07 102.905 106.4 107.870 112.40 114.82 118.69 121.75 127.60 126.904 131.30
76
Os
190.2
108
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
192.2 195.09 196.967 200.59 204.37 207.19 208.980 [210]
109
85
86
At
Rn
[210]
[222]
http://www.chemsoc.org/viselements/pages/periodic_table.html
Periodic Table: Metallic
arrangement
1
IA
1
• Layout of the Periodic Table: Metals vs.
nonmetals
2
IIA
13
IIIA
14
IVA
15
VA
18
VIIIA
16
VIA
17
VIIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
Metals
10
11
IB
12
IIB
Nonmetals
•Family: Are arranged vertically down the periodic table
(columns or
group, 1- 18 or I-VIII A)
•These elements have the same number electrons in the outer most shells, the
valence shell.
1
IA
1
18
VIIIA
Alkali Family:
1 e- in the valence shell
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
2
3
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
4
5
6
7
Halogen Family:
7 e- in the valence shell
17
VIIA
• Notable families of the Periodic Table
Halogen
Noble Gas
Chalcogens
Alkali
Alkaline
(earth)
1
IA
1
18
VIIIA
2
IIA
13
IIIA
Transition Metals
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
14
IVA
15
VA
16
VIA
17
VIIA
1
IA
1
H
2
Li
3
4
5
6
7
18
VIIIA
2
IIA
Na Mg
K
Ca
13
IIIA
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
Fe
9
VIIIB
10
11
IB
12
IIB
Cu Zn
Ag
14
IVA
15
VA
16
VIA
17
VIIA
C
N
O
F
Al Si
P
S
Cl
Br
I
He
e- configuration from the periodic
periodic table
1
IA
18
VIIIA
2
IIA
1
H
1s1
2
Li Be
2s1 2s2
Na Mg
3s1 3s2
3
4
5
6
7
13
IIIA
3
IIIB
4
IVB
Sc
3d1
Rb
5s1
Ca
4s2
Sr
5s2
Y
4d1
V
Ti
Cr Mn Fe Co
3d2 3d3 4s13d5 3d5 3d6 3d7
Zr Nb Mo Tc Ru Rh
4d2 4d3 5s14d5 4d5 4d6 4d7
Cs
6s1
Ba
6s2
La
5d1
Hf Ta W Re Os
5d2 5d3 6s15d5 5d5 5d6
Fr
7s1
Ra
7s2
Ac Rf
6d1 6d2
K
4s1
5
VB
6
VIB
7
VIIB
Db Sg Bh
6d3 7s16d5 6d5
8
9
VIIIB
14
IVA
15
VA
16
VIA
17
VIIA
B
2p1
•B
C
N
O
1
2
3
•2p
2p 2p 2p4
F
2p5
Ne
2p6
Al
3p1
Si
3p2
Cl
3p5
Ar
3p6
He
1s2
10
11
IB
12
IIB
Ni
3d8
Cu
4s13d10
Ni
4d8
5s14d10
Zn Ga Ge
3d10 4p1 4p2
Cd
In Sn
10
4d
5p1 5p2
As Se Be
4p3 4p4 4p5
I
Sb Te
5p3 5p4 5p5
Kr
4p6
Xe
5p6
Hg
Tl Pb
5d10 6p1 6p2
Bi Po At
6p3 6p4 6p5
Rn
6p6
Ir
Ni
7
5d 5d8
Hs Mt
6d6 6d7
Ag
Au
6s15d10
S
P
3
3p 3p4
electron behavior
• The periodic table can be classified by the behavior of their electrons
West (South)
METALS
Alkali
Alkaline
Transition
These elements
tend to give up
e - and form
CATIONS
1
IA
1
Mid-plains
METALLOID
These elements
will give up e- or
accept e-
East (North)
NON-METALS
Noble gas
Halogens
Calcogens
These elements
tend to accept
e - and form
ANIONS
2
IIA
13
IIIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
14
IVA
18
VIIIA
15
VA
16
VIA
17
VIIA
Warm Up
1) Where are metals located below?
2) What group is known as the halogens?
3) Where are the metalloids located?
1
IA
1
18
VIIIA
2
IIA
13
IIIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
14
IVA
15
VA
16
VIA
17
VIIA
Dmitri Mendeleev (1869)
Based on atomic mass
Today's periodic table organized by?
http://www.chem.msu.su/eng/misc/mendeleev/welcome.html
Periodic Trends
• Today we will rationalize observed trends in
– Atomic radius
– Ionization energy.
– Electronegativity
Periodic trends based on behavior of (-) electrons
and (+) protons
Valence Electrons- the outermost electrons that
surround an atom
Valence Electrons- starting with group 1 = 1 valence egroup 2 = 2 valence egroup 3A = 3 valence etrend continues to group 8A
•Atomic Radius:
Trends in Atomic Radius
•size of atom determine by boundaries of the valence e-.
•Atomic radius increases as you move down a group. Why?
•Atomic radius decreases as you move across a period. Why?
•Atomic Radius:
Trends in Atomic Radius
•size of atom determine by boundaries of the valence e-.
•Atomic radius increases as you move down a group. Why?
•Because you are adding more electrons to outer orbits
•Atomic radius decreases as you move across a period. Why?
•Atomic Radius:
Trends in Atomic Radius
•size of atom determine by boundaries of the valence e-.
•Atomic radius increases as you move down a group. Why?
•Because you are adding more electrons to outer orbits
•Atomic radius decreases as you move across a period. Why?
•Adding more e- BUT also adding MORE P+ which pull in e-
•Atomic Radius:
Trends in Atomic Radius
•size of atom determine by boundaries of the valence e-.
•Atomic radius increases as you move down a group. Why?
•Because you are adding more electrons to outer orbits
•Atomic radius decreases as you move across a period. Why?
•Adding more e- BUT also adding MORE P+ which pull in e-
Trends in Atomic Radius
•Place the following in order of increasing atomic
radius
•S, P, Ar, Cl, Si
Trends in Atomic Radius
•Place the following in order of increasing atomic
radius
•Ar, Cl, S, P, Si
•Atomic Radius:
Trends in Atomic Radius
Trends in Ionization Potential
Ionization potential:
Energy required to remove valence electron from atom.
Trends in Ionization Potential
As you move across a period, ionization energy increases.
WHY? - As you move across a period, the atomic radius
decreases, (atom gets smaller). The outer electrons are closer to
+ nucleus and more strongly attracted to + center. Therefore, it
requires more energy to remove electron
Trends in Ionization Potential
As you move down a group, ionization energy decreases.
WHY?
Electrons are further from the nucleus and thus easier to
remove
“e- SHIELDING" - Inner electrons block protons force of
attraction on outer e-. therefore easier to remove outer
electron
Trends in Ionization Potential
Place the following in order of increasing ionization
energy:
Mg, Ra, Sr, Ca, Ba,Be
Trends in Ionization Potential
Place the following in order of increasing ionization
energy:
Ra, Ba, Sr, Ca, Mg, Be
Trends in Electronegativity
The ability of an atom to attract (steal) electrons to itself:
Trends in Electronegativity
The ability of an atom to attract (steal) electrons to itself:
Which is more electronegative?
K or S and why?
Trends in Electronegativity
The ability of an atom to attract (steal) electrons to itself:
Which is more electronegative?
S why? b/c small radius of atom means the + nucleus
can attract the –e from other atoms
Summary of Trend
• Periodic Table and Periodic Trends
• 1. Electron Configuration
3. Ionization Energy: Largest toward NE of PT
4. Electron Negativity: Most favorable NE of PT
2. Atomic Radius: Largest toward SW corner of PT
Periodic Table Patterns
• Elements in the same
group generally have
similar chemical
properties.
• Properties are not
identical, however.
Periodic Table Patterns
Dmitri Mendeleev
came to the
conclusion that
Elements in the
same group
generally have
similar chemical
properties.
Periodic Table Predictions
Mendeleev, for instance, predicted the
discovery of germanium (which he called ekasilicon) as an element with an atomic weight
between that of zinc and arsenic, but with
chemical properties similar to those of silicon.
Electron Configurationenergy stair levels
Electrons are found in orbits.
an orbital is the shape of the
space where there is a high
probability of finding electrons
The s orbitals are spheres
This is the shape of p orbitals
z
The three 2p orbitals,
2px, 2py, 2pz
y
x
once each 2p orbital
is filled with a pair
of electrons, then
the 3s orbital
gets the next
two electrons
the 3s electrons
have a higher energy
than 1s, 2s, or 2p
electrons,
so 3s electrons are
generally found
further from the
nucleus than 1s,
2s, or 2p electrons
Summary of Trend
• Periodic Table and Periodic Trends
• 1. Electron Configuration
3. Ionization Energy: Largest toward NE of PT
4. Electron Negativity: Most favorable NE of PT
2. Atomic Radius: Largest toward SW corner of PT
once each 2p orbital
is filled with a pair
of electrons, then
Electron Configurationenergy stair levels
General Rules
• Aufbau Principle
– Electrons fill
lowest energy
orbitals first.
– “Lazy Occupant Rule”
General Rules
• Hund’s Rule
– Within a sublevel, place one e- per orbital
before pairing them e- repel each other
– “Empty Room Rule”
WRONG
RIGHT
General Rules
• Pauli Exclusion Principle
– Each orbital can hold TWO electrons with
opposite spins.
Electron Notations
• Orbital Diagram
O
8e-
1s
2s
• Electron Configuration
2
2
4
1s 2s 2p
2p
• Longhand e- Configuration
S 16e- 1s2 2s2 2p6 3s2 3p4
Core Electrons
Valence Electrons
• Shorthand e- Configuration
S
16e
2
4
[Ne] 3s 3p
J.J. Thomson used cathode ray
tube to discover electron
Atomic Review
Atomic Nomenclature
35
Mass #
Cl
Symbol
17
# protons
Periodic Law- elements increase by atomic number and have
a periodic trend or repetition of physical & chemical properties
Average atomic mass- mass on PT
Based on abundance of isotopes
1)Change % to decimal
2)Multiply decimal by the mass
3)Add the numbers together
Electron Configuration
Al 1s22s22p63s23p1
s
p
d
© 1998 by Harcourt Brace & Company
e- configuration table
1s
1s
2s
2p
3s
3p
4s
3d
4p
5s
4d
5p
6p
6s
La
5d
7s
Ac
6d
4f
5f
The Periodic Table
s1
1
2
3
4
5
6
7
s2
d1
d2
d3
d4
d5
d6
d7
d8
d10 p1
d9
p2
p3
p4
p5
p6
1
2
H
He
3
4
Li Be
11
12
Na Mg
19
20
5
6
7
8
B
C
N
O
F Ne
13
14
15
16
17
P
S
33
34
Al Si
21
22
23
24
25
26
27
28
29
30
31
32
9
10
18
Cl Ar
35
36
K Ca Sc Ti
V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
37
41
38
39
40
42
43
44
45
46
47
48
49
50
51
52
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te
55
56
57
72
73
74
75
76
77
78
Cs Ba La Hf Ta W Re Os Ir
87
88
89
104
105
106
107
108
79
80
81
f
84
I
Xe
85
86
109
110
111
114
116
118
Uuq
Uuh
Uuo
112
f1 f2 f3 f4 f5 f6 f7 f8 f9 f1 f1 f1 f1 f1
d
p
83
54
Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub
s
82
53
58
4
5
59
60
61
62
63
64
65
66
067
168
269
370
471
99
100
101
102
103
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
90
91
92
93
94
95
96
97
98
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
C. Periodic Patterns
• Example - Hydrogen
1
2
3
4
5
6
7
1
1s
1st Period
1st column
of s-block
s-block
Electron Configuration
• F
• Cl
• Al
• Br
Orbital Diagrams
F
Cl
Al
Br


  
1s
2s
2p
3s
3p


  

  
1s
2s
2p
3s


  

1s
2s
2p


1s
2s
4s
3d
4p
3p
4s
3d
4p
3s
3p
4s
3d
4p
  

  

    
  
2p
3s
3p
4s
3d
4p

Electron Configuration
• F 1s22s22p5
• Cl 1s22s22p63s23p5
• Al 1s22s22p63s23p1
• Br 1s22s22p63s23p64s23d104p5
Write Orbital and Electron
Configurations
• N
• Si
• Mg
• Ga
Orbital Diagrams
N
Si
Mg
Ga



 
1s
2s
2p
3s


  

1s
2s
2p
3s


  

1s
2s
2p


1s
2s
3p
4s
3d
4p
3p
4s
3d
4p
3s
3p
4s
3d
4p
  

  

    
2p
3s
3p
4s
3d



4p
Electron Configuration
• N 1s22s22p3
• Si 1s22s22p63s23p2
• Mg 1s22s22p63s2
• Ga 1s22s22p63s23p64s23d104p1
• Now write the above in short hand configuration
Electron Configuration
• N [He]2s22p3
Electron Configuration
• Si [Ne]3s23p2
Electron Configuration
• Mg [Ne]3s2
Electron Configuration
• Ga [Ar]4s23d104p1
Periodic Patterns
• Example - Germanium
1
2
3
4
5
6
7
[Ar]
2
4s
10
3d
2
4p
• Notable families of the Periodic Table
Halogen
Noble Gas
Chalcogens
Alkali
Alkaline
(earth)
1
IA
1
18
VIIIA
2
IIA
13
IIIA
Transition Metals
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
10
11
IB
12
IIB
14
IVA
15
VA
16
VIA
17
VIIA
Electron Stability
• Full energy level
• Full sublevel (s, p, d, f)
• Half-full sublevel
1
2
3
4
5
6
7
Stability
• Electron Configuration Exceptions
– Copper
EXPECT:
ACTUALLY:
[Ar] 4s2 3d9
[Ar] 4s1 3d10
– Copper gains stability with a full
d-sublevel.
“5 Facts 5 Pictures” Review
Interesting Fact 1- define or
explain
Interesting Fact 3
define or explain
[picture]
[Picture]
Most Important Concept or Fact 5Describe and explain What you learned
[Picture]
Interesting Fact 2- define or explain
[picture]
Interesting Fact 4- define
or explain
[picture]
J.J. Thomson used cathode ray
tube to discover electron
Atomic Review
Atomic Nomenclature
35
Mass #
Cl
Symbol
17
# protons
Periodic Law- elements increase by atomic number and have
a periodic trend or repetition of physical & chemical properties
Average atomic mass- mass on PT
Based on abundance of isotopes
1)Change % to decimal
2)Multiply decimal by the mass
3)Add the numbers together
Electron Configuration
Al 1s22s22p63s23p1
D. Stability
• Electron Configuration Exceptions
– Chromium
EXPECT:
ACTUALLY:
[Ar] 4s2 3d4
[Ar] 4s1 3d5
– Chromium gains stability with a half-full dsublevel.
Stability
• Ion Formation
– Atoms gain or lose electrons to become more
stable.
– Noble Gases .
1
2
3
4
5
6
7
D. Stability
• Ion Electron Configuration
– Write the e- config for the closest Noble Gas
– EX: Oxygen ion  O2-  Ne
O2-
10e-
[He] 2s2 2p6
4. Trend in Electron Affinity
Electron Affinity:
The energy release
when an electron is
added to an atom.
Most favorable
toward NE corner of
PT since these atoms
have a great affinity
for e-.
Periods- left to right
Groups- up & down, numbered 1-18 or 1A-8A,
Representative Elements- Group A Elements,
Group 1, 2, & 13-18 (8 groups represented)