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Chapter 5
The Periodic Table
1
Section 5.1
ORGANIZING ELEMENTS
2
A. Section 1: Organizing Elements
a. Dmitri Mendeleev was the first to
design a way of organizing elements
3
i.
Arranged elements in rows by increasing
atomic masses
ii. Started a new row each time chemical
properties repeated
iii. Left gaps in his list for elements that had
not been discovered yet
iv. Some elements did not fit Mendeleev’s
pattern
4
b. Henry Moseley arranged elements by
atomic numbers
i. Most elements did not change their
location, but a few did
5
c. The modern periodic table organizes
elements by atomic number
d. When the elements are arranged this
way, elements that have similar properties
appear at regular intervals (periodic law)
6
7
e. Period: each row of the periodic table
i. There are 7 periods on the periodic table
ii. As you move to the right across a
period, elements become less metallic
8
f. Groups: each column on the periodic table
i. each group has similar chemical
properties
ii. There are 18 groups on the periodic
table
9
10
Section 1 review
• 1. Describe how Mendeleev
organized his periodic table
– By increasing atomic masses
– Started a new row each time chemical
properties repeated
– Left gaps for undiscovered elements
11
Section 1 review
• 2. Explain why Mendeleev left a
space for the unknown (at the time)
element germanium in his periodic
table.
– The properties of germanium did not
match the next available group, so he
moved it over to the group whose
properties germanium did match, and
left a space
12
Section 1 review
• 3. State the property used to
organize elements in the modern
table.
–Atomic number
13
Section 1 review
• 4. Identify the following on the periodic
table:
a) The chemical symbol for mercury
 Hg
b) The period and group of gold
 Period 6
 Group 11
c) The atomic mass of iron
 55.845
14
Section 1 review
• 4. Identify the following on the periodic
table:
d) The atomic number of neon
 10
e) The element represented by Cu
 copper
15
Section 1 review
• 5. Metals conduct electricity well, while
nonmetals do not. Which element should
conduct electricity better: germanium,
aluminum or helium?
– aluminum
16
Section 1 review
• 6. Are the properties of sodium (Na) more
like the properties of lithium (Li) or
magnesium (Mg)? Explain your answer.
– Lithium—they are in the same group (column)
17
Section 1 review
• 7. Find oxygen (O), sulfur (S), and fluorine
(F) in the periodic table. Are the chemical
properties of O more similar to those of S
or F? Explain your answer.
– Sulfur—they are in the same group (column)
What is wrong here?!!!
18
Section 1 review # 8
Element
Symbol
Atomic
Number
Gold
Au
79
196.966569
6
11
silver
Ag
47
107.8682
5
11
calcium
Ca
20
40.078
4
2
Fe
26
55.845
4
8
iron
Atomic
Mass
Period
Group
19
Section 1 review
• 9. If scientists found element 117, into which period and
group would they place it? Identify one element that
would have properties similar to those of element 117.
– Period 7, group 17
– Like F, Cl, Br, I or At
20
Section 5.1
REVIEW
21
matching
•
•
•
•
•
•
•
•
•
_____
E 1. the repeating chemical & physical properties of elements change
periodically with the atomic numbers of the elements
G 2. a horizontal row of elements in the periodic table
_____
_____
F 3. a vertical column of elements in the periodic table
_____
A 4. Mendeleev arranged the elements in rows by increasing ___ ___.
B 5. The modern periodic table organizes elements by ___ ___.
_____
_____
I 6. the first man to design a way to organize the elements
_____
H 7. the man who arranged the elements by atomic number
_____
D 8. the number of periods on the periodic table
_____
C 9. the number of groups on the periodic table
•
•
•
A. atomic mass
E. periodic law
H. Moseley
B. atomic number
F. Group
I. Mendeleev
C. 18
G. period
D. 7
22
Use the periodic table:
Mo 10. the chemical symbol for molybdenum
• _____
5 11. what period is molybdenum in?
• _____
6 12. what group is molybdenum in?
• _____
42 13. the atomic number of molybdenum
• _____
95.94
• ____________
14. the atomic mass of molybdenum
Cr, W Sg
• _____ 15. the chemical symbol for an element that has
properties similar to molybdenum
23
Use the periodic table:
Os 16. the chemical symbol for osmium
• _____
6 17. what period is osmium in?
• _____
8 18. what group is osmium in?
• _____
76 19. the atomic number of osmium
• _____
190.23
• ____________
20. the atomic mass of osmium
Fe, Ru, Hs
• _____ 21. the chemical symbol for an element that has
properties similar to osmium
24
Use the periodic table:
Pt 22. the chemical symbol for platinum
• _____
6 23. what period is platinum in?
• _____
10 24. what group is platinum in?
• _____
78 25. the atomic number of platinum
• _____
• ____________
26. the atomic mass of platinum
195.084
Ni, Pd, Ds
• _____ 27. the chemical symbol for an element that has
properties similar to platinum
25
26
1
18
2
13 14 15 16 17
3
4
5
6
7
8
9
10 11 12
6
7
27
Practice:
Periodic Table and Valence
Electrons
28
Questions
• Definition of period
– Horizontal row
• Definition of group
– Vertical column
• What tells the # of valence electrons?
– Group number (for 13-18, subtract 10)
• What tells the number of energy levels?
– Period number
29
Chart
Element
symbol
Period
Group
Number of
valence e-
Number of
energy levels
C
2
14
4
2
Al
3
13
3
3
Cl
3
17
7
3
Sr
5
2
2
5
Fr
7
1
1
7
Ge
4
14
4
4
Be
2
2
2
2
Se
4
16
6
4
30
Chart
Element
symbol
Period
Group
Number of
valence e-
Number of
energy levels
Rb
5
1
1
5
Pb
6
14
4
6
P
3
15
5
3
At
6
17
7
6
F
2
17
7
2
Rn
6
18
8
6
Uuh
7
16
6
7
31
Section 5.2
EXPLORING THE
PERIODIC TABLE
32
B. Section 2: Exploring the Periodic Table
a. The periodic trends in the periodic table
are a result of electron arrangement
33
i. The chemical properties of each group are
determined by the number of valence
electrons
ii. The atoms of elements in the same
group have the same number of valence
electrons
Number of valence electrons
8
2
34
Number of Number of
Valence
Energy
eLevels
Element and
Symbol
Period
Group
Hydrogen, H
1
1
1
1
Nitrogen, N
2
15
5
2
Magnesium,
Mg
3
2
2
3
Potassium,
K
4
1
1
4
The period tells you the number of energy levels!!!
35
Element
and
Symbol
Group
Number of
Valence e-
Number of
Energy
Levels
Period
Iodine, I
5
17
7
5
Barium,
Ba
6
2
2
6
Radium,
Ra
7
2
2
7
The period tells you the number of energy levels!!!
36
b. Ion formation
i. Ionization: an atom may gain or lose
valence electrons so its outermost energy
level is full
37
ii. If an atom gains or loses electrons, it no
longer has an equal number of electrons
and protons
iii. Because the charges do not cancel
completely, the atom has a net electric
charge (ion)
2, 8, 1
2, 8, 7
Sodium: 11 protons
11 electrons
Chlorine: 17 protons
17 electrons
Sodium ion (+1): 11 protons
10 electrons
Chloride ion (-1): 17 protons
18 electrons
38
2, 8
2, 8, 8
iv. Group 1 elements
1. very reactive
2. have one valence electron which can
be easily removed
3. when an atom loses an electron it
becomes positive
All of this is true of hydrogen, although it
is NOT a full member of this group!
39
4. positive atoms are called cations and are
written with a superscript “+” next to the
element symbol
5. For example, a lithium (Li) ion with a
charge of +1 is written Li+ or Li1+ or Li+1
40
v. Group 17 elements
1. very reactive
2. have 7 valence electrons
3. needs only one more to become
stable
41
4. when an atom gains an electron, it is
called an anion, and is written with a
superscript “-” next to the element symbol
5. For example: a fluorine (F) ion with a
charge of -1 is written F- or F1- or F-1
42
vi. Other groups
1. Groups 2-16 can also form ions
2. have to lose or gain more than one
electron in order to fill their outermost
energy level
43
3. In general:
a. atoms with fewer than four valence
electrons lose electrons to form cations
(positive ions)
b. atoms with more than four valence
electrons gain electrons to form anions
(negative ions)
44
4. Ions of these elements are also indicated
with superscripts, however, the symbols
for these ions also show how many
electrons were gained or lost
5. For example: magnesium (Mg) loses its
two valence electrons to form a cation
Mg2+
45
c. How are elements classified
i. three categories: metals, nonmetals, and
semiconductors (metalloids)
46
Metals
Nonmetals
Semiconductors
metalloids
47
Three Categories of Elements
Category
Properties
Metals
good conductors of electricity and
thermal energy
ductile (easily formed into wires)
and malleable (easily shaped or
formed)
generally shiny solids
Example
Lead
48
Three Categories of Elements
Category
Properties
Example
Nonmetals
poor conductors of electricity and
thermal energy
not ductile or malleable
generally not shiny
may be solids, liquids, or gases
Carbon
49
Three Categories of Elements
Category
Properties
Semicondu
ctors
share properties with metals and
nonmetals
can conduct electricity under
certain circumstances
metalloids
Example
Tellurium
50
51
Ion Formation Practice
• 1. How do we find the number of valence
electrons an element has?
• Look at the group number
– 1 or 2 has 1 or 2 valence electrons
– 13-18: subtract 10 to get 3 – 8 valence
electrons
52
Ion Formation Practice
• 2. How many electrons can the folowing
electron levels hold?
2
– Level 1: _____
– Level 2: _____
8
18
– Level 3: _____
18 it is
• NOTE: although level 3 can hold ___,
full when 8 electrons are on it; all energy
levels (except level 1) are full with 8
electrons!!!
53
Ion Formation Practice
• 3. If an element is giving an electron
away…
– a. Will the ion formed be positive or
negative?
positive
– b. will the ion be a cation or anion?
cation
54
Ion Formation Practice
• 3. If an element is receiving an electron…
– a. Will the ion formed be positive or
negative?
negative
– b. will the ion be a cation or anion? anion
55
Ion Formation Practice
electrons needed
to fill outer
ion formed
energy level
element
group
# valence
electrons
cation or
anion?
Li
1
1
7
+1
cation
I
17
7
1
-1
anion
O
16
6
2
-2
anion
Ca
2
2
6
+2
cation
Mg
2
2
6
+2
cation
K
1
1
7
+1
cation
Ba
2
2
6
+2
cation
Cl
17
7
1
-1
anion56
Ion Formation Practice
electrons needed
to fill outer
ion formed
energy level
element
group
# valence
electrons
cation or
anion?
Sr
2
2
6
+2
cation
F
17
7
1
-1
anion
Rb
1
1
7
+1
cation
Na
1
1
7
+1
cation
S
16
6
2
-2
anion
Be
2
2
6
+2
cation
Ra
2
2
6
+2
cation
At
17
7
1
-1
anion
Fr
1
1
7
+1
cation
N
15
5
3
-3
anion
57
58
Section 2: Exploring the P.T.
• 1. Explain why elements in a group on the
periodic table have similar chemical
properties.
• they have the same number of valence
electrons
59
Section 2: Exploring the P.T.
• 2. Compare the number of valence
electrons in an atom of oxygen (O) with
the number of valence electrons in an
atom of selenium (Se). Are O and Se in
the same period or group?
• both have 6 valence electrons
• they are in the same group
60
Section 2: Exploring the P.T.
• 3. Explain why atoms gain or lose
electrons to form ions.
• they gain or lose electrons in order to have
a full outer level, which means 8 electrons
(except if it’s the first level, which is full
with 2 electrons)
61
Section 2: Exploring the P.T.
• 4. Describe why lithium (Li) and other
Group 1 elements usually form positive
ions, while fluorine (F) and other Group 17
elements form negative ions.
• group 1 elements lose one electron and
thus have a full outer level
• group 17 elements gain one electron and
thus have a full outer level
62
Section 2: Exploring the P.T.
• 5. List the three main categories of
elements, and give an example of each.
• metals—Cu, Ag, Au, Sn, Al, Na, Ca
• nonmetals—F, H, O, S, Ar, Br, Cl
• semiconductors (metalloids)—B, Si, Ge,
As, Sb, Te, Po, At
63
Section 2: Exploring the P.T.
• 6. Predict which ions cesium forms: Cs+
ions or Cs2+ ions.
• Cs+: it’s in group 1 and so gets rid of its
one valence electron to form a +1 ion
64
Section 2: Exploring the P.T.
• 7. Determine whether elements that fit the
following descriptions are more likely to be
metals or nonmetals:
a) a shiny substance used to make flexible bed
springs
•
metal
b) a yellow powder from underground mines
•
nonmetal
c) a gas that does not react
•
nonmetal
65
Section 2: Exploring the P.T.
• 7. Determine whether elements that fit the
following descriptions are more likely to be
metals or nonmetals:
d) a conducting material used within flexible
wires
•
metal
e) a brittle substance that does not conduct
heat
•
nonmetal
66
Section 2: Exploring the P.T.
• 8. Explain how a cation differs from an
anion.
• a cation is a positive ion that has more
protons than electrons and comes from an
element losing electrons
• an anion is a negative ion that has more
electrons than protons and comes from an
element gaining electrons
67
Section 2: Exploring the P.T.
• 9. Why do elements in groups share more
chemical properties than elements in a
period?
• in a group they have the same number of
valence electrons and will react in the
same manner either by giving or taking the
same number of electrons to become
stable
68
Section 2: Exploring the P.T.
• 10. Why do some atoms gain electrons to
form ions and some lose electrons?
• some atoms gain electrons because they
have 5 – 7 valence electrons and only
need 1 – 3 more electrons for a full outer
level
• some atoms lose electrons because they
have 1 – 3 valence electrons and will lose
those in order to reveal a full outer level
69
underneath
section 2
FLASHCARDS
70
5.2 flashcards
• The periodic trends in the periodic table
are the result of ___ ___.
– electron arrangement
• ion
– an atom, radical or molecule that has gained
or lost one or more electrons and has a
negative or positive charge
71
5.2 flashcards
• cation
– a positive ion
• anion
– a negative ion
• metal
– an element that is shiny and that conducts
heat and electricity well
72
5.2 flashcards
• nonmetal
– an element that conducts heat and electricity
poorly
• semiconductor
– an element or compound that conducts
electric current better than an insulator but not
as well as a conductor does
• metalloid
– another name for a semiconductor
73
Section 5.2
QUIZ REVIEW
74
Matching
C 1. other name for a semiconductor
• _____
B 2. an element that conducts
• _____
heat/electricity poorly
D 3. an element that conducts electric
• _____
current better than an insulator but not as
well as a conductor
F 4. a positive ion
• _____
E 5. a negative ion
• _____
• _____
A 6. an element that is shiny and
conducts heat/electricity well
• _____
G 7. an atom that has gained or lost
one or more electrons and has a positive
or negative charge
A. metal
B. nonmetal
C. metalloid
D. semiconductor
E. anion
F. cation
G. ion
75
Identify
B 8. ductile and malleable
• _____
A 9. not shiny
• _____
A 10. poor conductor of
• _____
heat/electricity
A 11. may be solids, liquids or
• _____
gases at room temperature
C 12. share properties with
• _____
metals and nonmetals
A. nonmetal
B. metal
C. metalloid
76
Chart
Element
Group
# valence
electrons
Electrons
needed to
fill outer
energy
level
Mg
2
2
6
+2
Cation
Se
16
6
2
-2
Anion
Al
13
3
5
+3
Cation
Br
17
7
1
-1
Anion
P
15
5
3
-3
Anion
K
1
1
7
+1
Cation
Ar
18
8
0
None
Ion formed
Cation or
anion
None 77
Fill-in with word bank
F 13. The periodic trends in the periodic
• _____
table are a result of ___ ___.
• _____ 14. The chemical properties of each
group are determined by the number of ___
___
• _____
E 15. Atoms with fewer than four
valence electrons ___ electrons
• _____ 16. Atoms with more than four valence
electrons ___ electrons.
A 17. If an element is giving an electron
• _____
away, the ion formed will be ___.
• _____ 18. If an element is receiving an
electron, the ion formed will be ___.
• _____
C 19. Atoms gain or lose electrons in
order to have a full ___ ___.
G
A. positive
B. negative
C. outer level
D. gain
E. lose
F. electron arrangement
G. valence electrons
D
B
78
Section 5.3
FAMILIES
OF ELEMENTS
79
C. Section 3: Families of Elements
a. Classifying elements further . . .
80
Group
Number
Number of Valence e-
Name of Family
Group 1
1
Alkali metals
Group 2
2
Alkaline-earth metals
Groups 3-12
Varied
Transition metals
Group 17
7
Halogens
Group 18
8 (except helium, which
has 2)
Noble Gases
81
b. Metals
i. Families of metals include alkali metals,
the alkaline-earth metals, and the
transition metals
zirconium
silver
tin
82
ii. Alkali metals:
1. elements in Group 1
2. very reactive
not H!!!
83
3. valence electron can be easily removed
to form a cation
4. similar physical properties: melting
point, boiling point, and density
Li
Na
K
Rb
84
5. Rarely found in nature as pure elements,
instead they are found combined with
other elements as compounds
6. For example: the alkali metal sodium (Na)
is found in the salt sodium chloride, NaCl
85
iii. Alkaline-earth metals:
1. elements in Group 2
2. have two valence electrons
3. not as reactive as alkali metals
4. form cations with 2+ charges
86
iv. Transition metals:
1. elements found in Groups 3-12
2. not as reactive, sometimes unreactive
87
3. can still form ions
4. some metals can form as many as four
different ions because of their complex
arrangement of electrons
88
v. Synthetic elements
1. elements with atomic numbers greater
than 92
2. made in a lab
3. radioactive and decay
4. may become different elements
89
5. Placed separately in the periodic table so
the rest of the periodic table stays narrow,
and it also allows the other elements to
line up according to periodic trends
6. Have various uses
90
c. Nonmetals
i. Noble Gases:
1. elements in Group 18
2. found as single atoms rather than
molecules
91
3. outermost energy level is filled
4. inert (unreactive)
5. very stable
92
ii. Halogens:
1. elements in Group 17
2. most reactive nonmetals
3. have seven valence electrons
4. combine easily with alkali metals
5. combinations are called salts
iodine
93
94
d. Semiconductors
i. can conduct electricity under certain
circumstances
ii. Contains six elements
1. Boron
2. Silicon
3. Germanium
4. Arsenic
5. Antimony
6. Tellurium
iii. Not found in a particular group
95
96
e. Hydrogen
i. has one valence electron
ii. Not a member of the alkali metals
iii. Most abundant element in universe
iv. Can react with many other elements
97
Section 5.3 Review
FAMILIES OF ELEMENTS
98
Section 3 Review
• Classify the following elements as alkali,
alkaline-earth, or transition metals based
on their positions in the periodic table.
– Iron (Fe) transition
– Potassium (K) alkali
– Strontium (Sr) alkaline earth
– Platinum (Pt) transition
99
Section 3 Review
• To which family does argon (Ar) belong?
– noble gases
• Describe why atoms of bromine (Br) are very
reactive. To which family does Br belong?
– Br is a member of the halogens
– halogens are the most reactive nonmetals
• Which element is more reactive: lithium (Li) or
beryllium (Be)? Explain your answer.
– Li
– alkali metals are more reactive than alkaline earth
metals
100
Section 3 Review # 5
Symbol
Group
number
Period
number
Family name
Co
9
4
Transition
B
13
Period 2
Semiconductor
At
17
Period 6
Halogen
Mg
Group 2
3
Alkaline earth
Xe
18
Period 5
Noble gas
101
section 5.3
QUIZ REVIEW
102
periodic table
I
J
F
Z
A
O
B
P
U
G
W
D
H
C
R
X
S
K
E
V
Y
L
T
Q
N
M
103
periodic table
1
am 2
1 I aem
2
3
Z
3 4
6 7
tm
A
4
B
O
G
W
6
D
H
C
R
X
P
U
5
7
5
18
17 ng
13 14 15 16 ha J
F
8 9 10 11 12
S
K
6 la
7 ac T
E
Q
V
Y
L
N
M
104
I
J
F
Z
A
O
B
P
U
G
W
D
H
C
R
X
S
K
E
Q
V
Y
L
T
N
M
AX
list all the alkali metals _________________________
ZR
list all the alkaline earth metals ___________________
O
list the metalloids ______________________________
IFGHSJPV
list the nonmetals ______________________________
105
I
J
F
Z
A
O
B
P
U
G
W
D
H
C
R
X
S
K
E
Q
V
Y
L
T
N
M
BUWDCKY
list the transition metals _________________________
JPV
list the noble gases _____________________________
SH
list the halogens _______________________________
E
list the elements with 3 electrons in the outer energy level __________________
106
Matching
B 1. most reactive metals
• _____
E 2. metals with 2
• _____
valence electrons that form 2+
cations
• _____
A 3. metals that can form
as many as 4 different ions
F 4. nonmetals that are
• _____
nonreactive
D 5. most reactive
• _____
nonmetals
C 6. most abundant
• _____
element in the universe
A.
B.
C.
D.
E.
F.
transition metals
alkali metals
hydrogen
halogens
alkaline earth metals
noble gases
107

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