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Chapter 5
The Periodic Table
1
ORGANIZING ELEMENTSSection 5.1
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
Do section 1review sheet
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)
18
What is wrong here?!!!
Section 1 review # 8
Element Symbol AtomicNumber
AtomicMass Period Group
Gold
47
4 2
Fe
19
679 196.966569Au 11
silver Ag 107.8682 5 11
calcium Ca 20 40.078
iron 26 55.845 4 8
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
REVIEWSection 5.1
21
matching• _____ 1. the repeating chemical & physical properties of elements change
periodically with the atomic numbers of the elements• _____ 2. a horizontal row of elements in the periodic table• _____ 3. a vertical column of elements in the periodic table• _____ 4. Mendeleev arranged the elements in rows by increasing ___ ___.• _____ 5. The modern periodic table organizes elements by ___ ___.• _____ 6. the first man to design a way to organize the elements• _____ 7. the man who arranged the elements by atomic number• _____ 8. the number of periods on the periodic table• _____ 9. the number of groups on the periodic table
• A. atomic mass B. atomic number C. 18 D. 7
• E. periodic law F. Group G. period • H. Moseley I. Mendeleev
22
E
GFABIHDC
Use the periodic table:• _____ 10. the chemical symbol for molybdenum
• _____ 11. what period is molybdenum in?
• _____ 12. what group is molybdenum in?
• _____ 13. the atomic number of molybdenum
• ____________ 14. the atomic mass of molybdenum
• _____ 15. the chemical symbol for an element that has properties similar to molybdenum
23
Mo
5
6
42
95.94
Cr, W Sg
Use the periodic table:• _____ 16. the chemical symbol for osmium
• _____ 17. what period is osmium in?
• _____ 18. what group is osmium in?
• _____ 19. the atomic number of osmium
• ____________ 20. the atomic mass of osmium
• _____ 21. the chemical symbol for an element that has properties similar to osmium
24
Os
6
8
76
190.23
Fe, Ru, Hs
Use the periodic table:• _____ 22. the chemical symbol for platinum
• _____ 23. what period is platinum in?
• _____ 24. what group is platinum in?
• _____ 25. the atomic number of platinum
• ____________ 26. the atomic mass of platinum
• _____ 27. the chemical symbol for an element that has properties similar to platinum
25
Pt
6
10
78
195.084
Ni, Pd, Ds
26
27
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
18
6
7
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 6 430
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
EXPLORING THE PERIODIC TABLE
Section 5.2
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
34
8Number of valence electrons
2
Element and Symbol
Period GroupNumber of
Valence e-
Number of Energy Levels
Hydrogen, H 1 1 1 1
Nitrogen, N 2 15 5 2
Magnesium, Mg
3 2 2 3
Potassium, K
4 1 1 4
35
The period tells you the number of energy levels!!!
Element and
SymbolPeriod Group
Number of Valence e-
Number of Energy Levels
Iodine, I 5 17 7 5
Barium, Ba
6 2 2 6
Radium, Ra
7 2 2 7
36
The period tells you the number of energy levels!!!
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)
38
Sodium: 11 protons 11 electronsChlorine: 17 protons 17 electrons
Sodium ion (+1): 11 protons 10 electronsChloride ion (-1): 17 protons 18 electrons
2, 8, 1 2, 8, 7
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 positiveAll 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
47
metalloids
Three Categories of Elements
Category Properties Example
Metals good conductors of electricity and thermal energyductile (easily formed into wires) and malleable (easily shaped or formed)generally shiny solids
Lead
48
Three Categories of Elements
Category Properties Example
Nonmetals poor conductors of electricity and thermal energynot ductile or malleablegenerally not shinymay be solids, liquids, or gases
Carbon
49
Three Categories of Elements
Category Properties Example
Semiconductors
share properties with metals and nonmetalscan conduct electricity under certain circumstances
Tellurium
50
metalloids
51
Do Ion FormationPractice Sheet
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?– Level 1: _____– Level 2: _____– Level 3: _____
• NOTE: although level 3 can hold ___, it is full when 8 electrons are on it; all energy levels (except level 1) are full with 8 electrons!!!
53
2
818
18
Ion Formation Practice
• 3. If an element is giving an electron away…– a. Will the ion formed be positive or
negative?– b. will the ion be a cation or anion?
54
positive
cation
Ion Formation Practice
• 3. If an element is receiving an electron…– a. Will the ion formed be positive or
negative?– b. will the ion be a cation or anion?
55
negative
anion
Ion Formation Practiceelement group
# valence electrons
electrons needed to fill outer
energy levelion formed
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
element group# valence electrons
electrons needed to fill outer
energy levelion formed
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 anion57
58
Do section 2 review sheet
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 underneath 69
FLASHCARDSsection 2
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
QUIZ REVIEWSection 5.2
74
Matching • _____ 1. other name for a semiconductor• _____ 2. an element that conducts
heat/electricity poorly• _____ 3. an element that conducts electric
current better than an insulator but not as well as a conductor
• _____ 4. a positive ion• _____ 5. a negative ion• _____ 6. an element that is shiny and
conducts heat/electricity well• _____ 7. an atom that has gained or lost
one or more electrons and has a positive or negative charge
75
A. metalB. nonmetalC. metalloidD. semiconductorE. anionF. cationG. ion
CB
D
FEA
G
Identify • _____ 8. ductile and malleable• _____ 9. not shiny• _____ 10. poor conductor of
heat/electricity• _____ 11. may be solids, liquids or
gases at room temperature• _____ 12. share properties with
metals and nonmetals
76
A. nonmetalB. metalC. metalloid
BAA
A
C
Chart
Element Group# valence electrons
Electrons needed to fill outer energy level
Ion formedCation or
anion
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 None77
Fill-in with word bank• _____ 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 ___ ___
• _____ 15. Atoms with fewer than four valence electrons ___ electrons
• _____ 16. Atoms with more than four valence electrons ___ electrons.
• _____ 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 ___.
• _____ 19. Atoms gain or lose electrons in order to have a full ___ ___.
78
A. positiveB. negativeC. outer levelD. gainE. loseF. electron arrangementG. valence electrons
F
G
E
D
A
B
C
FAMILIESOF ELEMENTS
Section 5.3
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
82
tin
zirconium
silver
ii. Alkali metals:
1. elements in Group 1
2. very reactive
83
not H!!!
3. valence electron can be easily removed to form a cation
4. similar physical properties: melting point, boiling point, and density
84
Li Na K Rb
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
93
iodine
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
metalloids
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
FAMILIES OF ELEMENTSSection 5.3 Review
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)– Potassium (K)– Strontium (Sr)– Platinum (Pt)
99
transition
alkali
alkaline earth
transition
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
metals100
Section 3 Review # 5Symbol Group
numberPeriod
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
QUIZ REVIEWsection 5.3
102
periodic table
103
I
A
Z
B
X K
W
C
Y
U
D
E
F
O
G
H
VQ
P
S
J
R
T
L
M
N
periodic table
104
I
A
Z
B
X K
W
C
Y
U
D
E
F
O
G
H
VQ
P
S
J
R
T
L
M
Nla
ac
ha
tm
am
aem
ng
1
1
2
2 3
3
4
4
5
5
6
6
7
7
8
6
7
9 10 11 12
13 14 15 16
17
18
105
I
A
Z
B
X K
W
C
Y
U
D
E
F
O
G
H
VQ
P
S
J
R
T
L
M
N
list all the alkali metals _________________________
list all the alkaline earth metals ___________________
list the metalloids ______________________________
list the nonmetals ______________________________
A X
Z R
I F G H S J P V
O
106
I
A
Z
B
X K
W
C
Y
U
D
E
F
O
G
H
VQ
P
S
J
R
T
L
M
N
list the transition metals _________________________
list the noble gases _____________________________
list the halogens _______________________________
list the elements with 3 electrons in the outer energy level __________________
B U W D C K Y
J P V
S H
E
Matching• _____ 1. most reactive metals • _____ 2. metals with 2
valence electrons that form 2+ cations
• _____ 3. metals that can form as many as 4 different ions
• _____ 4. nonmetals that are nonreactive
• _____ 5. most reactive nonmetals
• _____ 6. most abundant element in the universe
107
A. transition metalsB. alkali metalsC. hydrogenD. halogensE. alkaline earth metalsF. noble gases
B
E
A
F
D
C