Download Chapter 2 - Department of Chemistry and Physics

CHAPTER 2
Atoms,Elements, Periodic Table
1
Vocabulary
Chemistry
Science that describes matter – its
properties, the changes it undergoes,
and the energy changes that
accompany those processes
Matter
Anything that has mass and occupies
space.
2
Elements
Elements
substances that cannot be decomposed into
simpler substances via chemical reactions
Elemental symbols
found on periodic chart
First letter capital, second letter lower case
C, Ca, Co
CO is not an element.
3
4
5
The Periodic Table: Metals
Some properties of metals
1.
2.
3.
4.
5.
6.
7.
Form cations by losing electrons (+ charge)
Form ionic compounds with nonmetals
Typically solids (except mercury)
Shiny
Conduct Electricity
Ductile
Malleable
6
The Periodic Table: Metals,
Nonmetals, and Metalloids
Groups or families
Vertical group of elements on periodic table
Similar chemical and physical properties
7
The Periodic Table: Metals,
Nonmetals, and Metalloids
Period
Horizontal group of elements on periodic table
Transition from metals to nonmetals
8
The Periodic Table: Metals
Group IA metals
Alkali metals Li, Na, K, Rb, Cs, Fr
Group IIA metals
Alkaline earth metals
Be, Mg, Ca, Sr, Ba, Ra
9
The Periodic Table: Nonmetals
Some chemical properties of nonmetals
1. Form anions by gaining electrons (- charge)
2. Form ionic compounds with metals and
3.
4.
5.
6.
covalent compounds with other nonmetals
Noble gasses have full shells
Do not conduct electricity
Poor conductors
Typically gasses or solids.
10
The Periodic Table: Metals,
Nonmetals, and Metalloids
Group VIIA nonmetals
halogens
F, Cl, Br, I
11
The Periodic Table: Metals,
Nonmetals, and Metalloids
Group VIA nonmetals
Chalcogens
O, S, Se, Te
12
The Periodic Table: Metals,
Nonmetals, and Metalloids
Group VIIIA nonmetals
noble, inert or rare gases
He, Ne, Ar, Kr, Xe, Rn
13
The Periodic Table: Metals,
Nonmetals, and Metalloids
Stair step function on periodic table separates
metals from nonmetals.
Metals are to the left of stair
step.
Approximately 80% of the
elements
Nonmetals are to the right of
stair step.
Approximately 20% of the
elements
Metalloids have one side of the
box on the stair step.
Properties between metals and
nonmetals
14
The Periodic Table: Metals,
Nonmetals, and Metalloids
Periodic trends in metallic character
More Metallic
More
Metallic
Periodic
Chart
15
16
Atoms and Atomic Theory
1.
2.
3.
4.
5.
All matter is composed of extremely small, indivisible
particles called atoms.
All atoms of a given element have identical
properties that differ from those of other elements.
Atoms cannot be created, destroyed, or transformed
into atoms of another element.
Atoms of 2 or more elements can combine to form
compounds. These combine in fixed proportions
Chemical Reactions rearrange and recombine atoms
but do not destroy them.
17
Fundamental Particles
Three fundamental particles make up atoms. The
following table lists these particles together with
their masses and their charges.
P a rtic le
M a s s (a m u ) C h a rg e
-
E le c tro n (e )
0 .0 0 0 5 4 8 5 8
-1
P ro to n (p ,p + )
1 .0 0 7 3
+1
1 .0 0 8 7
0
0
N e u tro n (n ,n )
18
Structure of the Atom
1.
2.
3.
4.
The atom is mostly empty space.
It contains a very small, dense center called the
nucleus.
Nearly all of the atom’s mass is in the nucleus.
The nuclear diameter is 1/10,000 to 1/100,000
times less than atom’s radius.
19
Atomic Number
The atomic number is equal to the number of
protons in the nucleus.
Sometimes given the symbol Z.
Numbered consecutively on the periodic table
The atomic number determines the element .
The elements differ from each other by the
number of protons in the nucleus.
The number of electrons in a neutral atom is also
equal to the atomic number.
For charged species there are more electrons if it
is negative and less electrons if it is positive
20
Mass Number and Isotopes
Mass number is given the symbol A.
A is the sum of the number of protons and
neutrons.
Z = proton number N = neutron number
A=Z+N
A common symbolism used to show mass and
proton numbers is
A
Z
12
6
48
20
E for example C, Ca,
14
?
63
?
197
79
Au
18
8
N, Cu, ?
21
22
Isotopes
Isotopes are atoms of the same element but
with different numbers of neutrons.
Isotopes have different masses and A values but
are the same element.
One example of an isotopic series is the
hydrogen isotopes.
1H
or protium is the most common hydrogen
isotope.
one proton and no neutrons
2H
or deuterium is the second most abundant
hydrogen isotope.
one proton and one neutron
3H
or tritium is a radioactive hydrogen isotope.
one proton and two neutrons
23
24
Mass Number and Isotopes
•
How many protons and neutrons are in the
following? 16
+
23
O
8
Na
11
18
8
40
20
2+
238
92
82
35
−
O
U
236
92
U
Ca
32
16
Br
S
2−
25
Mass Number and Isotopes
Give the number of protons, neutrons and
electrons and the correct element symbol
24
12
?
200
79
15
7
?
?
26
Atomic Mass
The atomic mass of an element on the periodic table is the
weighted average of the masses of its stable isotopes
For example H = 1.008 amu
Calcium = 40.078 amu
We will use these masses later for chemical calculations
27
The role of the electron
Bohr’s Planetary Model of the atom:
1.
Atom has a number of discrete energy
levels (orbits, shells) in which an electron
may exist
As the orbital radius increases so does the energy
1<2<3<4<5......
1
2
3
28
The role of the electron
2. An electron may move from one energy
level (orbit) to another. Radiation is
emitted or absorbed
Energy is absorbed when electrons jump to higher orbits.
n = 2 to n = 4 for example
Energy is emitted when electrons fall to lower orbits.
n = 4 to n = 1 for example
29
Atomic Spectra and the Bohr
Atom
The principal quantum
number has the symbol – n.
n = 1, 2, 3, 4, ...... “shells”
n = K, L, M, N, ......
The electron’s energy depends
principally on n .
30
The role of the electron
31
The role of the electron
3. Each sell contains a region
where electrons move in a circular
orbit around the nucleus
Atomic Orbital (sub shell)
Atoms have electrons in s, p, d, or f orbitals.
32
Atomic Orbitals
Every orbital can hold up to two electrons.
The two electrons are designated as having
one spin up ↑ and one spin down ↓
The number of orbitals per n level is given
by n2.
The maximum number of electrons per n
level is 2n2.
The value is 2n2 because of the two paired
electrons.
33
Electrons per shell
Energy Level
n
1
2
# of Orbitals
n2
1 (s)
4 (s,p)
Max. # of e2n2
2
8
3
9 (s,p,d)
18
4
16 (s,p,d,f )
32
34
Atomic Orbitals
s orbital properties:
There is one s orbital per n level.
1s, 2s, 3s, 4s……
s orbitals are spherical
35
Atomic Orbitals
p orbital properties:
The first p orbitals appear in the n = 2 shell.
2p, 3p, 4p….
p orbitals are peanut or dumbbell shaped.
There are 3 p orbitals per n level
Each orbital holds 2 electrons, 6 total in
the p orbitals
36
Atomic Orbitals
d orbital properties:
The first d orbitals appear in the n = 3
shell. (3d,4d…)
There are 5 d orbitals
per n level.
With 2 electrons per
orbital
There are 10 electrons
In a d orbital
37
Atomic Orbitals
f orbital properties:
The first f orbitals appear
in the n = 4 shell.
(4f, 5f, 6f…)
There are seven f
orbitals per n level..
2 electrons per level
14 electrons total
38
Electron Configurations
39
The Periodic Table and
Electron Configurations
Use the periodic chart to figure out how the
shells fill up.
40
The Periodic Table and
Electron Configurations
Use the periodic chart to figure out how the
shells fill up.
41
The Periodic Table and
Electron Configurations
1st row elements.
1s
↑
1
H
2
He ↑↓
Configuration
1
1s
1s
2
42
The Periodic Table and
Electron Configurations
2nd row elements. (Hund’s rule)
1s
3 Li
2s
2p
↑↓ ↑
↑↓ ↑ ↓
4 Be
Configuration
1s 2 2s1
1s 2 2s 2
5B
↑↓ ↑ ↓ ↑
1s 2 2s 2 2p1
6C
↑↓ ↑ ↓ ↑ ↑
1s 2 2s 2 2p 2
7N
↑↓ ↑ ↓ ↑ ↑ ↑
1s 2 2s 2 2p3
8O
↑↓ ↑ ↓ ↑↓ ↑ ↑
1s 2 2s 2 2p 4
9F
↑↓ ↑ ↓ ↑↓ ↑↓ ↑
1s 2 2s 2 2p5
2
2
6
Ne
1s
2s
2p
↑↓
↑
↓
↑↓
↑↓
↑↓
10
43
The Periodic Table and
Electron Configurations
3rd row elements
3s
11 Na
12
Mg
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
[Ne] ↑
[Ne] ↑↓
[Ne] ↑↓
[Ne] ↑↓
[Ne] ↑↓
[Ne] ↑↓
[Ne] ↑↓
[Ne] ↑↓
3p
Configuration
↑
↑ ↑
↑ ↑ ↑
↑↓ ↑ ↑
↑↓ ↑↓ ↑
↑↓ ↑↓ ↑↓
[Ne] 3s1
[Ne] 3s2
[Ne] 3s2 3p1
[Ne] 3s2 3p2
[Ne] 3s2 3p3
[Ne] 3s2 3p4
[Ne] 3s2 3p5
[Ne] 3s2 3p6
44
The Periodic Table and
Electron Configurations
4th row elements
3d
19 K [Ar ]
4s
↑
4p
Configuration
[Ar ] 4s1
45
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
↑↓
Ca [Ar ]
4p
Configuration
[Ar ] 4s1
2
[Ar ] 4s
46
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar ]
↑↓
21
Sc You do it!
4p
Configuration
[Ar] 4s1
[Ar] 4s2
47
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar ]
↑↓
Sc [Ar ] ↑
↑↓
21
4p
Configuration
[Ar] 4s1
2
[Ar] 4s
[Ar] 4s2 3d1
48
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar ]
↑↓
Sc [Ar ] ↑
↑↓
21
4p
Configuration
[Ar ] 4s1
[Ar ] 4s2
[Ar ] 4s2 3d1
Ti You do it!
22
49
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar ]
↑↓
Sc [Ar ] ↑
↑↓
Ti [Ar ] ↑ ↑
↑↓
21
22
4p
Configuration
[Ar ] 4s1
[Ar ] 4s2
[Ar ] 4s2 3d1
[Ar ] 4s2 3d2
50
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar ]
↑↓
Sc [Ar ] ↑
↑↓
22
Ti [Ar ] ↑ ↑
↑↓
23
V [Ar ] ↑ ↑ ↑
↑↓
21
4p
Configuration
[Ar ] 4s1
[Ar ] 4s2
[Ar ] 4s2 3d1
[Ar ] 4s2 3d 2
[Ar ] 4s2 3d3
51
The Periodic Table and
Electron Configurations
3d
4s
19 K [Ar ]
↑
20
Ca [Ar]
↑↓
Sc [Ar] ↑
↑↓
22
Ti [Ar] ↑ ↑
↑↓
23
V [Ar] ↑ ↑ ↑
↑↓
Cr [Ar] ↑ ↑ ↑ ↑ ↑
↑
21
24
4p
Configuration
[Ar] 4s1
[Ar] 4s2
[Ar] 4s2 3d1
[Ar] 4s2 3d2
[Ar] 4s2 3d3
[Ar] 4s1 3d5
There is an extra measure of stability associated
with half - filled and completely filled orbitals.
52
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
4s
↑↓
4p
Configurat ion
[Ar ] 4s 2 3d 5
53
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑
26
↑ ↑ ↑ ↑
4s
↑↓
4p
Configurat ion
[Ar ] 4s 2 3d 5
Fe You do it!
54
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
26
Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
4s
↑↓
↑↓
4p
Configurat ion
[Ar ] 4s 2 3d 5
[Ar ] 4s 2 3d 6
55
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
26 Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
27 Co [Ar ] ↑↓ ↑↓ ↑ ↑ ↑
4s
↑↓
↑↓
↑↓
4p
Configurat ion
[Ar ] 4s2 3d 5
[Ar ] 4s2 3d 6
[Ar ] 4s2 3d 7
56
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
26
27
28
4s
↑↓
Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
↑↓
Co [Ar ] ↑↓ ↑↓ ↑ ↑ ↑
↑↓
Ni [Ar ] ↑↓ ↑↓ ↑↓ ↑ ↑
↑↓
4p
Configurat ion
[Ar ] 4s2 3d 5
[Ar ] 4s2 3d 6
[Ar ] 4s2 3d 7
[Ar ] 4s2 3d 8
57
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
4s
↑↓
Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
↑↓
Co [Ar ] ↑↓ ↑↓ ↑ ↑ ↑
↑↓
28
Ni [Ar ] ↑↓ ↑↓ ↑↓ ↑ ↑
↑↓
29
Cu You do it!
26
27
4p
Configurat ion
[Ar ] 4s 2 3d 5
[Ar ] 4s 2 3d 6
[Ar ] 4s 2 3d 7
[Ar ] 4s 2 3d 8
58
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
26
27
28
29
4s
4p
↑↓
Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
↑↓
Co [Ar ] ↑↓ ↑↓ ↑ ↑ ↑
↑↓
Ni [Ar ] ↑↓ ↑↓ ↑↓ ↑ ↑
↑↓
Cu [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
Another exception like Cr and
for essentiall y the same reason.
Configuration
[Ar ] 4s2 3d 5
[Ar ] 4s2 3d 6
[Ar ] 4s2 3d 7
[Ar ] 4s2 3d8
[Ar ] 4s1 3d10
59
The Periodic Table and
Electron Configurations
3d
25 Mn [Ar ] ↑ ↑ ↑ ↑ ↑
26
27
28
29
30
4s
↑↓
Fe [Ar ] ↑↓ ↑ ↑ ↑ ↑
↑↓
Co [Ar ] ↑↓ ↑↓ ↑ ↑ ↑
↑↓
Ni [Ar ] ↑↓ ↑↓ ↑↓ ↑ ↑
↑↓
Cu [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
Zn [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓
4p
Configuration
[Ar ] 4s2 3d 5
[Ar ] 4s2 3d 6
[Ar ] 4s2 3d 7
[Ar ] 4s2 3d8
[Ar ] 4s1 3d10
[Ar ] 4s2 3d10
60
The Periodic Table and
Electron Configurations
3d
4s
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
4p
Configurat ion
[Ar ] 4s 2 3d10 4p1
61
The Periodic Table and
Electron Configurations
3d
4s
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
4p
Configurat ion
[Ar ] 4s 2 3d10 4p1
Ge You do it!
62
The Periodic Table and
Electron Configurations
3d
4s
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
4p
Ge [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
Configurat ion
[Ar ] 4s 2 3d10 4p1
[Ar ] 4s 2 3d10 4p 2
63
The Periodic Table and
Electron Configurations
3d
4s
4p
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
33
Ge [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
As [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑
Configurat ion
[Ar ] 4s 2 3d10 4p1
[Ar ] 4s 2 3d10 4p 2
[Ar ] 4s 2 3d10 4p 3
64
The Periodic Table and
Electron Configurations
3d
4s
4p
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
Ge [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
33
As [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑
34
Se You do it!
Configurat ion
[Ar ] 4s 2 3d10 4p1
[Ar ] 4s 2 3d10 4p 2
[Ar ] 4s 2 3d10 4p 3
65
The Periodic Table and
Electron Configurations
3d
4s
4p
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
33
34
Ge [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
As [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑
Se [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
Configurat ion
[Ar ] 4s 2 3d10 4p1
[Ar ] 4s 2 3d10 4p 2
[Ar ] 4s 2 3d10 4p 3
[Ar ] 4s 2 3d10 4p 4
66
The Periodic Table and
Electron Configurations
3d
4s
4p
Configurat ion
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
32
33
34
35
Ge [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
As [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑
Se [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑
Br [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
[Ar ] 4s 2 3d10 4p1
[Ar ] 4s 2 3d10 4p 2
[Ar ] 4s 2 3d10 4p 3
[Ar ] 4s 2 3d10 4p 4
[Ar ] 4s 2 3d10 4p5
67
The Periodic Table and
Electron Configurations
3d
4s
4p
Configurat ion
31 Ga [Ar ] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑
[Ar ] 4s 2 3d10 4p1
2
10
2
[
]
[
]
Ge
Ar
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑
↑
Ar
4s
3d
4p
32
2
10
3
[
]
[
]
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑
↑
↑
As
Ar
Ar
4s
3d
4p
33
2
10
4
[
]
[
]
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑
↑
Se
Ar
Ar
4s
3d
4p
34
2
10
5
[
]
[
]
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑
Br
Ar
Ar
4s
3d
4p
35
2
10
6
[
]
[
]
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
Kr
Ar
Ar
4s
3d
4p
36
68
More About the Periodic Table
Electron configurations—similar leads to
similar properties.
Noble Gases
All of them have completely filled electron
shells.
Since they have similar electronic
structures, their chemical reactions are
similar.
He
Ne
Ar
Kr
Xe
Rn
1s2
[He] 2s2 2p6
[Ne] 3s2 3p6
[Ar] 4s2 4p6
[Kr] 5s2 5p6
[Xe] 6s2 6p6
69
More About the Periodic Table
Representative
Elements
Are the elements in A
groups on periodic chart.
These elements will have
their “last” electron in an
outer s or p orbital.
These elements have
fairly regular variations in
their properties.
70
More About the Periodic Table
d-Transition Elements
Elements on periodic chart in B
groups.
Sometimes called transition
metals.
Each metal has d electrons.
ns (n-1)d configurations
These elements make the
transition from metals to
nonmetals.
Exhibit smaller variations from
row-to-row than the
representative elements.
71
More About the Periodic Table
f - transition metals
Sometimes called inner transition
metals.
Electrons are being added to f
orbitals.
Electrons are being added two
shells below the valence shell!
Consequently, very slight
variations of properties from
one element to another.
Outermost electrons have
the greatest influence on the
chemical properties of
elements.
72