Transcript ionization energy - Old Saybrook Public Schools

IMPORTANT CONTRIBUTORS
1. Dobereiner (1780-1849)
- classified elements with
similar properties in groups of
three –
TRIADS
2. Newlands (1837-1898)
a. If elements are arranged in
order of increasing atomic
mass
b. then, properties repeat
every 8 elements
Law of Octaves
3. MEYER (1830-1895)
- noticed a repeating pattern in the
properties of the elements
- graphed these patterns
MENDELEEV – 1869
First useable periodic table
a) Arranged elements in order
of increasing atomic mass
& similar properties
b) Left “gaps” where no known
element existed
1. Predicted elements would be found to fill the
gaps (and their properties):
Ga, Ge, Hf, Sc
c) This arrangement produced some anomalies.
Ex. The positions of I & Te had to be switched so that
they would be arranged according to their properties.
Mendeleev’s Predicted Properties of Germanium
(“eka Silicon”) and Its Actual Properties
Property
atomic mass
appearance
density
molar volume
specific heat capacity
oxide formula
oxide density
sulfide formula
and solubility
chloride formula
(boiling point)
chloride density
element preparation
Predicted Properties
of eka Silicon (E)
Actual Properties of
Germanium (Ge)
72amu
gray metal
5.5g/cm3
13cm3/mol
0.31J/g*K
EO2
4.7g/cm3
ES2; insoluble in H2O;
soluble in aqueous (NH4)2S
ECl4; (<1000C)
72.61amu
gray metal
5.32g/cm3
13.65cm3/mol
0.32J/g*K
GeO2
4.23g/cm3
GeS2; insoluble in H2O;
soluble in aqueous (NH4)2S
GeCl4; (840C)
1.9g/cm3
reduction of K2EF6 with
sodium
1.844g/cm3
reduction of K2GeF6 with
sodium


WILLIAM RAMSAY
In 1890’s
Discovered most of the Noble
Gases (Ne, Ar, Kr, Xe)
MOSELEY- 1913-1915
a.
Bombarded various metals with
cathode rays (high speed
electrons).
b. X-rays were given off. He
observed that the frequencies
of the X-rays increased by the
same factor as he went from
element to element.
c. Hypothesized: Difference in frequencies was due
to amount of positive charge in the nucleus
Correlated the frequency to a whole number; this
became the atomic number!
"We have here a proof that there
is in the atom a fundamental quantity,
which increases by regular steps as
we pass from one element to the next.
This quantity can only be the change
on the central positive nucleus, of the
existence of which we already have
definite proof."
d. When elements are arranged in the Periodic Table in
order of this “atomic number”, I & Te fall into their
“correct” places on the table.
e. He left gaps and predicted the existence of elements to
fill them (ex. Rh).
PERIODIC LAW
The chemical and physical properties of the elements
are periodic functions of their ATOMIC NUMBER.
Certain characteristics reappear at regular
intervals.
ORGANIZATION OF THE PERIODIC TABLE
a. Periods (Series)
1. Period number gives:
the number of occupied energy levels
2. Transition elements:
Periods 4, 5, 6, 7 – center block
3. Inner transition elements:
Periods 6 and 7
Lanthanide series:
#58 – 71 (Ce – Lu)
Actinide series
# 90 – 103 (Th – Lr)
1A
(1)
1
2
3
Period
4
5
6
7
8A
(18)
1
H
1.008
2A
(2)
3A
(13)
4A
(14)
5A
(15)
6A
(16)
7A
(17)
2
He
4.003
3
Li
6.941
4
Be
9.012
5
B
10.81
6
C
12.01
7
N
14.01
8
O
16.00
9
F
19.00
10
Ne
20.18
11
Na
22.99
12
Mg
24.31
3B
(3)
4B
(4)
5B
(5)
6B
(6)
7B
(7)
(8)
(9)
(10)
1B
(11)
2B
(12)
13
Al
26.98
14
Si
28.09
15
P
30.97
16
S
32.07
17
Cl
35.45
18
Ar
39.95
19
K
39.10
20
Ca
40.08
21
Sc
44.96
22
Ti
47.88
23
V
50.94
24
Cr
52.00
25
Mn
54.94
26
Fe
55.85
27
Co
58.93
28
Ni
58.69
29
Cu
63.55
30
Zn
65.39
31
Ga
69.72
32
Ge
72.61
33
As
74.92
34
Se
78.96
35
Br
79.90
36
Kr
83.80
37
Rb
85.47
38
Sr
87.62
39
Y
88.91
40
Zr
91.22
41
Nb
92.91
42
43
44
45
46
47
Ag
107.9
48
Cd
112.4
49
In
114.8
50
Sn
118.7
51
Sb
121.8
52
Te
127.6
53
I
126.9
54
Xe
131.3
55
Cs
132.9
56
Ba
137.3
57
La
138.9
72
Hf
178.5
73
Ta
180.9
74
W
183.9
75
Re
186.2
76
Os
190.2
77
Ir
192.2
78
Pt
195.1
79
Au
197.0
80
Hg
200.6
81
Tl
204.4
82
Pb
207.2
83
Bi
209.0
84
Po
(209)
85
At
(210)
86
Rn
(222)
87
Fr
(223)
88
Ra
(226)
89
Ac
(227)
104
Rf
(261)
105
Db
(262)
106
Sg
(266)
107
Bh
(262)
108
Hs
(265)
109
Mt
(266)
110
111
112
(269)
(272)
(277)
68
Er
167.3
69
Tm
168.9
70
Yb
173.0
71
Lu
175.0
100
Fm
(257)
101
Md
(258)
102
No
(259)
103
Lr
(260)
TRANSITION ELEMENTS
8B
Mo
Tc
Ru metals
Rh
Pd
Transition
95.94
(98)
101.1 102.9 106.4
INNER TRANSITION ELEMENTS
6
7
Lathanides
Actinides
58
Ce
140.1
59
Pr
140.9
60
Nd
144.2
61
Pm
(145)
90
Th
232.0
91
Pa
(231)
92
U
238.0
93
Np
(237)
Ideal Gas Constant: R=0.0821 L atm mol-1K-1
1 atm = 760 mm Hg = 760 torr
62
63
64
65
66
Lanthanide
series
Sm
Eu
Gd
Tb
Dy
150.4
152.0
157.3
158.9
162.5
67
Ho
164.9
94
Pu
(242)
95
Am
(243)
96
Cm
(247)
97
Bk
(247)
98
Cf
(251)
99
Es
(252)
Actinide series
b. Number of elements known today:
118
c. GROUPS (or FAMILIES):
vertical columns
GROUPS
or
FAMILIES
 GROUPS:

or FAMILIES
1A:
Alkali Metals
 2A:
Alkaline Earth Metals
 7A:
Halogens
 8A:
Noble Gases
1A
(1)
1
4
5
6
7
11
Na
22.99
19
K
39.10
37
Rb
85.47
55
Cs
132.9
87
Fr
(223)
TRANSITION ELEMENTS
4
Be
9.012
8B
3A
(13)
4A
(14)
5A
(15)
6A
(16)
7A
(17)
2
He
4.003
5
B
10.81
6
C
12.01
7
N
14.01
8
O
16.00
9
F
19.00
10
Ne
20.18
17
Cl
35.45
18
Ar
39.95
35
Br
79.90
36
Kr
83.80
53
I
126.9
54
Xe
131.3
85
At
(210)
86
Rn
(222)
12
Mg
24.31
3B
(3)
4B
(4)
5B
(5)
6B
(6)
7B
(7)
(8)
(9)
(10)
1B
(11)
2B
(12)
13
Al
26.98
14
Si
28.09
15
P
30.97
16
S
32.07
20
Ca
40.08
21
Sc
44.96
22
Ti
47.88
23
V
50.94
24
Cr
52.00
25
Mn
54.94
26
Fe
55.85
27
Co
58.93
28
Ni
58.69
29
Cu
63.55
30
Zn
65.39
31
Ga
69.72
32
Ge
72.61
33
As
74.92
34
Se
78.96
38
Sr
87.62
39
Y
88.91
40
Zr
91.22
41
Nb
92.91
42
Mo
95.94
43
Tc
(98)
44
Ru
101.1
45
Rh
102.9
46
Pd
106.4
47
Ag
107.9
48
Cd
112.4
49
In
114.8
50
Sn
118.7
51
Sb
121.8
52
Te
127.6
56
Ba
137.3
57
La
138.9
72
Hf
178.5
73
Ta
180.9
74
W
183.9
75
Re
186.2
76
Os
190.2
77
Ir
192.2
78
Pt
195.1
79
Au
197.0
80
Hg
200.6
81
Tl
204.4
82
Pb
207.2
83
Bi
209.0
84
Po
(209)
88
Ra
(226)
89
Ac
(227)
104
Rf
(261)
105
Db
(262)
106
Sg
(266)
107
Bh
(262)
108
Hs
(265)
109
Mt
(266)
110
111
112
(269)
(272)
(277)
INNER TRANSITION ELEMENTS
6
Lathanides
58
Ce
140.1
59
Pr
140.9
60
Nd
144.2
61
Pm
(145)
62
Sm
150.4
63
Eu
152.0
64
Gd
157.3
65
Tb
158.9
66
Dy
162.5
67
Ho
164.9
68
Er
167.3
69
Tm
168.9
70
Yb
173.0
71
Lu
175.0
7
Actinides
90
Th
232.0
91
Pa
(231)
92
U
238.0
93
Np
(237)
94
Pu
(242)
95
Am
(243)
96
Cm
(247)
97
Bk
(247)
98
Cf
(251)
99
Es
(252)
100
Fm
(257)
101
Md
(258)
102
No
(259)
103
Lr
(260)
Ideal Gas Constant: R=0.0821 L atm mol-1K-1
1 atm = 760 mm Hg = 760 torr
Noble Gases
Halogens
Period
Alkali metals
3
3
Li
6.941
2A
(2)
Alkaline Earth metals
2
1
H
1.008
8A
(18)
Can also be named with: a common
element from the group
Oxygen Group
 5A: Nitrogen Group
 4A: Carbon Group
 6A:
d. HYDROGEN: Unique element
What does family/group
mean?
 Elements
with similar chemical
properties have similar
arrangements of their outershell eWhat are these called?
 Octet
Valence e-
Rule: Atoms will tend to gain,
share and lose valence electrons in
order to achieve a full outer shell.
TRANSITION METALS
a.
B group elements (or Groups 3 – 12)
ex. Copper group:
Cu, Ag, Au, Uuu
1. Most common metals
2. Characteristics:
a. Generally less reactive than other metals
- Cu does not react with water, but Group 1A
metals react explosively
b. Have higher melting points than other metals
c. Form colored compounds:
Fe: green
Cu: blue, green
Mn: purple
Cr: yellow, orange
d. Form alloys with other metals
Brass (Cu & Zn)
Sterling silver
Atomic Radius
a. Definition:
One half the distance between adjacent
nuclei (1/2 D)
Distance (D)
b. Moving left to right across the period (with
increasing atomic number),
atomic radius decreases
Why?
Increasing nuclear charge pulling on the same
number of energy levels draws the electron cloud in
closer and closer.
(Shielding effect constant)
c. Shielding effect: Refers to the shielding of the
outer energy level from the pull of the nucleus.
Increases with more energy levels between the
nucleus and the outer level.
d. Moving down in a group (with
increasing atomic number,
atomic radius INCREASES.
Why?
Down a group
Each time go down in a
group, an energy level is
added.
(energy levels between
nucleus and outershell shield
outershell from effect of
nucleus)
Increase
radius
Metals
1. Location:
Left side of the Periodic Table
2. Characteristics:
a. Good conductors of heat and electricity
b. Shiny luster
c. Malleable—can be hammered into shape
d. Color: Usually silver (grey) except for gold
(Au) and Copper (Cu)
e. State: Solid at room temperature. (except
Hg)
f. Ductile—can be drawn into wire
g. Tend to LOSE electrons
NONMETALS
1. Location: right side of Periodic Table
2. Characteristics:
a. States:
Solids & gases (Except Bromine)
b. Poor conductors of heat and electricity
c. Colors: Various
d. Brittle (not malleable)
e. Dull luster
f. Tend to GAIN electrons
METALLOIDS (Semimetals)
1. Location: Along the zigzag line (either side)
2. They include:
B, Si, As, Te, Ge, Sb, Po
3. Properties of metals and nonmetals
4. Some are semiconductors
Si, Ge
Ionization Energy
Outtershell Electrons are Valence
Electrons
1. Energy needed to remove an e- from
Positive Charge
each atom in a mole
- Forms a ions
e- 4 N
3 P e-
e- 4 N
3 P ee-
Ex. Na + 496 kJ  Na+1 + 1 eIonization energy
HOW ABOUT GROUPS AND PERIODS?
1. Moving down in a GROUP (with increasing atomic
number),
Ionization energy decreases from top to bottom.
Why?
Outershell electrons get farther from the nucleus,
( more shielding by inner energy levels from effects
of the nucleus),so less energy is required to remove
the electron.
2. Within a period (with increasing atomic number),
ionization energy increases.
Why?
Increasing nuclear charge pulling on the same # of
energy levels binds outershell electrons more
strongly (shielding effect constant), requiring more
energy to remove them.
3. Is this a periodic property?
Yes.
4. Metals:
LOW Ionization Energy
5. Nonmetals
HIGH Ionization Energy
Successive Ionization Energies
The 1st ionization energy of an element is the Energy
needed to remove the FIRST e- from an atom.
 The 2nd ionization energy is the energy needed to
remove the SECOND e- from an atom.
 The 3rd ionization energy is the energy needed to
remove the THIRD e- from an atom.

5N
e- e- 4 P
e-
e-
As more e- are removed, what
happens to ionization E?

As more e- are removed, one would expect successive
ionization energies to increase.
 Why?
As more electrons are removed, the nucleus holds onto
the remaining e- more and more tightly.
e-
5N
e- 4 P
e-
e-
Successive Ionization Energies of Period 3
Elements (kJ/mole)
Elemen 1st
2nd
3rd
4th
5th
6th 7th
t
Na
Mg
Al
Si
P
S
Cl
Ar
496
4,562
738
1,451
7,733
578
1,817
2,745
11,157
787
1,577
3,232
4,356
16,091
1,012
1,907
2,914
4,964
6,274
21,267
1,000
2,252
3,357
4,556
7,004
8,496
27,101
1,251
2,298
3,822
5,159
6,542
9,362
11,018
1,521
2,666
3,931
5,771
7,238
8,781
11,995
How does the jump in ionization energies noted in the
diagram relate to the arrangement of electrons in each of
the atoms?
It occurs after the outer shell electrons are removed.
How is the jump related to the number of outer shell
electrons?
By locating the “jump” one can determine the number of
outershell (valence) electrons.
Why does the jump in ionization energies occur?
The big jump occurs because the electrons remaining are
in a lower energy level, much closer to the nucleus, and so
are more strongly attracted by it.
 An
unknown element has the following
successive ionization energies:




1st ionization energy: 589 kJ/mol
2nd ionization energy: 1,144 kJ/mol
3rd ionization energy: 4,906 kJ/mol
4th ionization energy: 6,465 kJ/mol
 What
is this elements family?
Alkaline earth metals
 How many valence e- does it have?
2 valence e-
An unknown element has the
following successive ionization
energies:
1st ionization energy: 578 kJ/mol
2nd ionization energy: 1,817 kJ/mol
3rd ionization energy: 2,745 kJ/mol
4th ionization energy: 11,577 kJ/mol
What is this elements family?
Aluminum family
How many valence e- does it have?
3 valence e-
Electron Affinity
DEFINITION:
Energy released or absorbed when an electron is gained
by an atom.
1.
2.
Results in the formation of an ion with a negative charge.
ex. F + 1 e-  F- + 328 kJ
a. reflects how tightly an extra electron is bound
more negative:
tightly bound
low & positive:
loosely bound
more positive: very loosely bound
b. GENERALIZATION:
NONMETALS: negative electron affinities
(exception: NOBLE GASES)

Which group has the highest e- affinity
(most strongly attracts a e-)?
 Why?
Electronegativity

1.
2.
3.
Measures the e- attracting power of an
atom when it bonds with another atom
Uses a relative number scale
Reflects both ionization energy and
electron affinity
Fluorine–highest electronegativity
•
= 4.0
4. LOW ionization energy –
LOW electronegativity
METALS
HIGH ionization energy –
HIGH electronegativity
NONMETALS
Electronegativity increases
Left  Right in a period,
electronegativity
increases.
Atoms are getting smaller,
increasing the effect of the
nucleus on the outer shell
electrons.
Electronegativity
decreases
Going DOWN in a group, electronegativity
decreases.
Atoms get larger, decreasing the pull of the nucleus on the
outershell electrons.
5. He, Ne, Ar of noble gases are not given a
value 
They do not form compounds
6. Atoms with LOW electronegativity –
WEAK attraction for electrons in a bond
7. Atoms with HIGH electronegativity
STRONG attraction for electrons in a bond
METALLIC CHARACTER
 Metals get more active as they
move:
 Left and down
 Most active
metal?
Francium (Fr)
NONMETALLIC CHARACTER
 Nonmetals get more active as they
move
 Right and up
 Exclude noble
gases
 Most active
nonmetal?
Fluorine (F)
Periodic Table trends can be understood
in terms of 3 basic rules
1. Electrons are attracted to the protons in the nucleus of an atom.
 The closer an electron is to the nucleus, the more strongly it
is attracted.
 The more protons in a nucleus, the more strongly an electron
is attracted.
2. Electrons are repelled by other electrons in an atom. So if other
electrons are between a valence electrons and the nucleus,
the valence electrons will be less attracted to the nucleus.
That is called shielding.
3. Completed shells (and to a lesser extent, completed subshells)
are very stable.