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Chapter Three
Atomic Structure
and the
Periodic Table
Atomic Structure and the Periodic Table
cont’d
Recall our understanding of an element.
Element is matter that ______ be broken down into
a simpler substance by ________ or _________
means.
Recall our understanding of an atom.
Atom is the ________ particle of an element that can
exist and still have the properties of the element.
Chapter 3 | Slide 2
Atomic Structure and the Periodic Table
cont’d
Now we will discuss ATOMIC STRUCTURE and
Sub-Atomic Particles
An atom is composed of a _______ and an area
called the electron _____
» The nucleus is very small compared to the size of the
atom
» The nucleus contains the _______ (+) and the _______
» The __________ (-) are constantly moving around in
the electron cloud
» In a neutral atom, the number of electrons (-) is
_______ to the number of protons (+)
Chapter 3 | Slide 3
Atomic Structure and the Periodic Table
cont’d
← Fig. 3.1 Nuclear
Model of the Atom
The protons and
neutrons of an atom
are found in the
central nuclear region,
or nucleus, and the
electrons are found in
an electron cloud
outside the nucleus.
Chapter 3 | Slide 4
Atomic Structure and the Periodic Table
cont’d
Charge
Actual Mass
(g)
Relative Mass
Electron
Proton
Neutron
-1
+1
0
9.109 X 10-28
1.673 X 10-24
1.675 X 10-24
1
1837
1839
e = 1 mass unit
Chapter 3 | Slide 5
Atomic Structure and the Periodic Table
cont’d
Atomic Symbols
Mass number =
number of protons +
number of neutrons
Charge =
A
Z
X
Q
number of protons –
number of electrons
Atomic number =
number of protons
Chapter 3 | Slide 6
Atomic Structure and the Periodic Table
cont’d
# _________ = Atomic Number Z
Atoms have no charge,
# __________ = # __________ = Z
# Neutrons = ______ Number (A) - # _________ (Z)
Chapter 3 | Slide 7
Atomic Structure and the Periodic Table
cont’d
Electrons are arranged around the nucleus of an
atom
Electrons can be _____ to, _______ from or
_______ with other atoms
When lost or gained, atoms become _______ (ions)
Lost electrons result in _____charged ion, ________
Gained electrons result in _____ charged ion, _____
# Protons in nucleus ________ changes, _________
arrangement determine chemical properties
Chapter 3 | Slide 8
Atomic Structure and the Periodic Table
cont’d
Atomic Symbol
vs
Periodic Table
20
40
20
Ca
2+
Ca
40.08
Chapter 3 | Slide 9
Atomic Structure and the Periodic Table
cont’d
• How many electrons,
neutrons, and protons are
in the following particles?
# protons
#electrons
#neutrons
40Ca
40Ca2+
14C
12C
Chapter 3 | Slide 10
Atomic Structure and the Periodic Table
cont’d
# Protons remains constant
# Neutrons can vary
Mass numbers of atoms of same element will vary
depending on the # neutrons in the nucleus
Atoms that differ in # neutrons are called Isotopes
Chapter 3 | Slide 11
Atomic Structure and the Periodic Table
cont’d
Most elements have naturally occurring __________
Number of isotopes can range from two to ten
Example: Silicon, Si exists in three isotopic forms
All Si atoms have 14 protons and 14 electrons
Most, 92.21% contain 14 neutrons
Some, 4.70% contain 15 neutrons
Some, 3.09% contain 16 neutrons
Chapter 3 | Slide 12
Atomic Structure and the Periodic Table
cont’d
They have the following notations
28
Si
14
29
Si
14
30
Si
14
Chapter 3 | Slide 13
Atomic Structure and the Periodic Table
cont’d
The additional neutrons in the nucleus may have
very slight effects on the chemical properties of
the element, and some measurable effects on
some physical properties such as melting points,
boiling points and Densities. See Chemical
Connections on pg 55 in text.
Chapter 3 | Slide 14
Atomic Structure and the Periodic Table
cont’d
The atomic mass is expressed in atomic mass units
amu
• atomic mass unit
• Defined as 1/12th the mass of 12C
• 1 amu = the mass of 1 proton or 1 neutron
The atomic mass that is found on the periodic table
or used for calculations is a weighted average of
the atomic masses for the isotopes
Chapter 3 | Slide 15
Atomic Structure and the Periodic Table
cont’d
• To get the average mass of an element, you must add
together the mass contributions of each different
isotope
» % abundance x isotopic mass = mass contribution
• Calculate the average atomic mass of Chlorine if
75.53% of the atoms are 35Cl (34.97 amu) and 24.47%
of the atoms are 37Cl (36.97 amu).
(0.7553 x 34.97 amu) + (0.2447 x 36.97 amu) =
35.46 amu
Chapter 3 | Slide 16
Atomic Structure and the Periodic Table
cont’d
Chapter 3 | Slide 17
Atomic Structure and the Periodic Table
cont’d
→ Table 3.2
Isotopic Data for
Elements with
Atomic Numbers 1
through 12
Chapter 3 | Slide 18
Atomic Structure and the Periodic Table
cont’d
Early 1800s, scientists searched for some order in
the chemical information known at that time
Certain elements had properties that were very
similar to those of other elements
Method or Arrangement was sought that would be
consistent with this information
Chapter 3 | Slide 19
Atomic Structure and the Periodic Table
cont’d
John Newlands (1865)
Arranged elements in order of increasing atomic mass
When he did this, he noticed that there were chemical and
physical properties that repeated every eight elements
“law of octaves”
Chapter 3 | Slide 20
Atomic Structure and the Periodic Table
cont’d
→ Fig. 3.2
Mendeleev constructed a periodic
table as part of his effort to
systemize chemistry.
Edgar Fahs Smith Collection, University of
Pennsylvania Library
Chapter 3 | Slide 21
Atomic Structure and the Periodic Table
cont’d
Dmitri Mendeleev and Julius Lothar Meyer
independently proposed ideas or relationships
regarding the periodicity of __________ and
increasing atomic ________ or atomic _________.
Modern Periodic Law states that when elements are
arranged in order of increasing atomic number,
elements with similar chemical properties occur at
periodic or regularly recurring intervals.
Chapter 3 | Slide 22
Atomic Structure and the Periodic Table
→ CO 3.1
Music consists of a series
of tones that build octave
after octave. Similarly,
elements have properties
that recur period after
period.
Novastock/PhotoEdit
Chapter 3 | Slide 23
Chapter 3 | Slide 24
Atomic Structure and the Periodic Table
cont’d
Elements with similar chemical properties are
positioned in _________ ___________
These _________ _________ are called ________
The ____________ ______ of elements are called
____________
Note the _________ are numbered sequentially 1-7
The ________ are identified by two notations, using
Roman numerals and letters, or numbered
sequentially 1-18
Chapter 3 | Slide 25
Chapter 3 | Slide 26
Chapter 3 | Slide 27
Atomic Structure and the Periodic Table
cont’d
Also note that Element 72 follows Element 57, as
does Element 104 follows Element 89
The missing elements 58 through 71 and 90 through
103 are located in two rows at the bottom of the
periodic table.
Positioned here for convenience.
See the periodic table in the next slide with these rows
positioned where they should be located.
Chapter 3 | Slide 28
Atomic Structure and the Periodic Table
cont’d
Fig. 3.4
In this periodic table, elements 58 through 71 and 90 through 103 are
shown in their proper positions.
Chapter 3 | Slide 29
Chapter 3 | Slide 30
Atomic Structure and the Periodic Table
cont’d
Common Names for some Groups
Group IA – Alkali Metals, excluding H
Soft, shiny and readily react with water
Group IIA – Alkaline earth metals
Soft, shiny and moderately reactive toward water
Group VIIA – Halogens
Reactive, colored, gases at or slightly above room
temperatures
Group VIII – Nobel Gases
Generally unreactive, that undergo few, if any, chemical reactions
Chapter 3 | Slide 31
Atomic Structure and the Periodic Table
cont’d
Chapter 3 | Slide 32
Atomic Structure and the Periodic Table
cont’d
Fig. 3.5
(a) Some familiar metals are
aluminum, lead, tin, and
zinc.
(b) Some familiar nonmetals
are sulfur, phosphorus,
and bromine.
Chapter 3 | Slide 33
Atomic Structure and the Periodic Table
cont’d
← Fig. 3.6
This portion of the
periodic table shows the
dividing line between
metals and nonmetals.
Chapter 3 | Slide 34
Atomic Structure and the Periodic Table
cont’d
Electrons are arranged around the nucleus of an
atom
Electrons can be lost to, gained from or shared with
other atoms
When lost or gained, atoms become charged (ions)
Lost electrons result in + charged ion, cation
Gained electrons result in – charged ion, anion
Inference: Electrons are special and we will
learn are related to the chemical properties of
an element
Chapter 3 | Slide 35
Atomic Structure and the Periodic Table
cont’d
• The space outside the nucleus in an atom is called
the ___________ ____________
» The _________ ________ is subdivided into
different ___________ (positioned according
to energy each electron possesses
• Shells are subdivided into ____________
› Subshells are subdivided into __________
○ Each orbital contains _____ electrons
Chapter 3 | Slide 36
Atomic Structure and the Periodic Table
cont’d
•
Electron Shell
» A region of space about a nucleus that contains electrons that have
approximately the same energy and that spend most of their time
approximately the same distance from the nucleus
•
1st shell
» Can contain up to 2 electrons
•
2nd shell
» Can contain up to 8 electrons
•
3rd shell
» Can contain up to 18 electrons
•
4th shell
» Can contain up to 32 electrons
•
Any shell can contain up to 2n2 electrons, where n is the shell number
Chapter 3 | Slide 37
Atomic Structure and the Periodic Table
cont’d
• Subshell
» A region of space within an electron shell that contains
electrons that have the same __________
» Four different kinds of subshells: s, p, d, and f
» Shell 1: contains s subshell
» Shell 2: contains s and p subshells
» Shell 3: contains s, p, and d subshells
» Shell 4: contains s, p, d, and f subshells
Chapter 3 | Slide 38
Atomic Structure and the Periodic Table
cont’d
→ Fig. 3.7
The number of subshells
within a shell is equal to the
shell number.
Chapter 3 | Slide 39
Atomic Structure and the Periodic Table
cont’d
• Orbital
» Region of space where two electrons are found
» Have different shapes depending on which subshell
they are in (shape of region of space not electrons)
» There are a different number of orbitals in each kind of
subshell
•
•
•
•
In an s subshell, there is 1 orbital
In a p subshell, there are 3 orbitals
In a d subshell, there are 5 orbitals
In a f subshell, there are 7 orbitals
Chapter 3 | Slide 40
Atomic Structure and the Periodic Table
cont’d
Fig. 3.8
An s orbital has spherical shape; a p orbital has two lobes; a d orbital
has four lobes; and an f orbital has eight lobes.
Chapter 3 | Slide 41
Atomic Structure and the Periodic Table
cont’d
Fig. 3.9
Orbitals within a subshell differ mainly in orientation.
Chapter 3 | Slide 42
Atomic Structure and the Periodic Table
cont’d
• There are ____ electrons in each ________
» The electrons move around in the __________
» One of the electrons spins __________
» One of the electrons spins ______________________
Chapter 3 | Slide 43
Chapter 3 | Slide 44
Atomic Structure and the Periodic Table
cont’d
• Electron configurations tells us in which subshells
the electrons for an element are located.
• Three rules:
» 1. Electrons fill orbitals starting with lowest energy first
» 2. There can be no more than 2 electrons in any orbital,
and those electrons must have different spins
» 3. For orbitals in the same subshell, electrons fill each
orbital singly before any orbital gets a second electron
Chapter 3 | Slide 45
Atomic Structure and the Periodic Table
cont’d
←Fig. 3.10
The order of filling
various electron
subshells. Subshells
of different shells
“overlap.”
How will you
remember the order?
Chapter 3 | Slide 46
Atomic Structure and the Periodic Table
cont’d
→ Fig. 3.11
The order of filling various
electron subshells with
electrons follows the same
order given by the arrows in
this diagram.
Chapter 3 | Slide 47
Atomic Structure and the Periodic Table
cont’d
Writing Electronic Configurations
H 1s1
He 1s2
Li 1s2, 2s1
Ne 1s2, 2s2, 2p6
Na 1s2, 2s2, 2p6, 3s1
Ar 1s2, 2s2, 2p6, 3s2, 3p6
K 1s2, 2s2, 2p6, 3s2, 3p6, 4s1
K [Ar] 4s1
Kr 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6
Kr [Ar] 4s2, 3d10, 4p6
Chapter 3 | Slide 48
Atomic Structure and the Periodic Table
cont’d
Electronic Configurations of Transition Elements
Fe 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6
Br 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p5
Pb 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10,
5p6, 6s2, 4f14, 5d10, 6p2
Chapter 3 | Slide 49
Atomic Structure and the Periodic Table
cont’d
• Which of the following electron configurations is
correct for
»
»
»
»
»
A)
B)
C)
D)
E)
Chapter 3 | Slide 50
Atomic Structure and the Periodic Table
cont’d
Give the symbol of the element that has:
A. [Ar]4s2 3d6
B. Four 3p electrons
C. Two electrons in the 4d sublevel
D. The element that has the electron configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d2
1s2 2s2 2p6 3s2 3p6 3d4
Chapter 3 | Slide 51
Atomic Structure and the Periodic Table
cont’d
Drawing Orbital Diagrams
• First, write out the electron configuration
• Start drawing the orbital diagram
» --1 orbital (blanks) for every s subshell
» --3 orbitals(blanks) for every p subshell
» --5 orbitals (blanks) for every d subshell
• Blanks are circles or squares
Chapter 3 | Slide 52
Atomic Structure and the Periodic Table
cont’d
Orbital Diagrams
↑↓
↑
Li
1s2
Na
↑↓
1s2
Na1+
2s1
↑↓
2p
↑↓
2s2
↑↓
↑↓
1s2
2s2
↑↓
3s
↑↓
2p6
↑↓
↑↓
2p6
3p
↑
3s1
3p
↑↓
3s
3p
Chapter 3 | Slide 53
Atomic Structure and the Periodic Table
cont’d
Orbital Diagrams
↑↓
↑↓
N
1s2
O
↑↓
1s2
O2-
↑
2s2
↑↓
↑↓
1s2
2s2
↑
2p3
↑↓
2s2
↑↓
↑
↑
↑↓
2p6
3p
3s
3p
↑
2p4
↑↓
3s
↑↓
3s
3p
Chapter 3 | Slide 54
Atomic Structure and the Periodic Table
cont’d
← CC 3.3
The different colors of
fireworks result when heat
excites the electrons of
different kinds of metal
atoms.
William S. Helsel/Getty Images
Chapter 3 | Slide 55
Chapter 3 | Slide 56
Atomic Structure and the Periodic Table
cont’d
Electron Configuration and the Periodic Law
We said that elements in the same group have
similar chemical reactivities
» Electrons are the subatomic particles involved in
chemical reactions
• Which electrons are most likely to be involved in
chemical reactions?
» A) those nearest to the nucleus
» B) those farthest from the nucleus
» C) all are equally likely to be involved
Chapter 3 | Slide 57
Atomic Structure and the Periodic Table
cont’d
• What differentiates one family from another?
» Let’s look at the electron configurations (valance electron
configurations) of the alkali metals to find out.
•
•
•
•
•
•
Li
Na
K
Rb
Cs
Fr
Chapter 3 | Slide 58
Atomic Structure and the Periodic Table
cont’d
• Elements with similar properties have the same
type of distinguishing electron! (_________
electrons)
• The last electron added to the electron configuration for
an element when electron subshells are filled in order of
increasing energy
• It is also the one that causes an element’s electron
configuration to differ from that of the element
immediately preceding it in the periodic table
Chapter 3 | Slide 59
Chapter 3 | Slide 60
Chapter 3 | Slide 61