Transcript day4-periodictrends

Do Now
Work silently. Raise hand to ask Ms.
Hughes anything.
1. Which family is least reactive?
2. Which family is most metallic?
3. Where are the nonmetals on the periodic
table?
Announcements
• Unit 4 test tomorrow
• If you have not taken 3 chemistry tests yet
this semester, see me after to arrange a
make up
• Retake GLEs for GRADE BOOST
Mystery Element
• Definitely NOT a Metalloid
• 3rd Most Common Element in Earth’s
Crust
• Light weight / Good Conductor
• Because it is a good conductor, it
makes a great beverage can…but its
resistance to corrosion means lots of
space in land fills
Valence Electrons
Don’t forget!
• Valence electrons are the
electrons in the outermost
energy level.
Example
• Electron configuration for silicon (Si):
• What is the highest energy level?
• So how many valence electrons?
2
2
6
2
2
1s 2s 2p 3s 3p
2 + 2 = 4!
Valence Electrons
Family/Group
Alkali Metals
Alkaline Earth Metals
Boron’s Group
Carbon’s Group
Nitrogen’s Group
Oxygen’s Group
Halogens
Noble Gases
Number of Valence Electrons
What is Atomic Size?
• Atomic size is…
–How big an atom is
–Also known as atomic
radius
Graphing Atomic Size (Radii)
• Draw 2 line graphs
–X-axis: Element
–Y-axis: Atomic Radius
(picometers)
Elements and their Atomic Radii
(1)
-12
1 picometer = 1 x 10
m
Element
Atomic Radius
Hydrogen
37
Lithium
152
Sodium
186
Potassium
227
Rubidium
248
Cesium
265
Elements and their Atomic Radii
(2)
-12
1 picometer = 1 x 10
Element
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
m
Atomic Radius
152
112
85
77
75
73
72
71
Atomic Size – Graph 1
Atomic Radius (picometer)
350
300
250
200
150
100
50
0
0
1
H
2
Li
3
Na
4
K
Element
5
Rb
6
Cs
7
Atomic Size – Graph 2
Atomic Radius (picometer)
160
140
120
100
80
60
40
20
0
0
Li
2
Be
B
C4
6
N
O
Element
F
8
Ne
10
What trend(s)
do
you notice?
Atomic size DECREASES as you go across the Periodic Table
Atomic size INCREAESES as you go down the
Periodic Table
Atomic Size
Key Point #1: Atomic size
increases as you go down the
periodic table and to the left
Practice Problems
• Rank the following elements in order of
increasing atomic size based on location
on the periodic table (smallest to biggest)
Fr, Sc, P, Pd
P, Pd, Sc, Fr
F, As, Tl, S
Fluorine, Sulfur, Arsenic, Thallium
Practice Time!
1.
T or F? Atomic size decreases as you move right across the
periodic table.
2. T or F? As you move down the Periodic Table, atoms get
smaller.
3. Rank the following sets of elements in order of increasing
atomic size (small  big).
Set A: Bh, Mn, Re, Tc Set B: Sb, I, Ag, Ru
Set C: Y, Ti, Sg, Ta
4. Rank the following sets of elements in order of decreasing
atomic size (big  small).
Set A: Cl, At, I, F, Br Set B: Te, Xe, Sn, In
Set C: Rb, K, Sr, Ca
How metallic?
• How metallic an element is changes
periodically too!!
• Hard, shiny, solid, conducts electricity,
malleable, ductile
• Same pattern as atomic radii
• Elements become more metallic as you
move left and down on the periodic table
What is electronegativity?
• Electronegativity is…
–The ability of an atom to attract
electrons
–How much an atom wants
electrons
–How easily an atom accepts
electrons
Graphing Electronegativity
• Draw 2 line graphs
–X-axis: Element
–Y-axis: Electronegativity
(Paulings)
Elements and their
Electronegativity (1)
Element
Electronegativity
Hydrogen
2.20
Lithium
0.98
Sodium
0.93
Potassium
0.82
Rubidium
0.82
Cesium
0.79
Francium
0.70
Elements and their
Electronegativity (2)
Element
Electronegativity
Lithium
0.98
Beryllium
1.57
Boron
2.04
Carbon
2.55
Nitrogen
3.04
Oxygen
3.44
Fluorine
3.98
Electronegativity Graph 1
2.5
Electronegativity
2
1.5
1
0.5
0
0
1
2
3
4
Element
5
6
7
8
Electronegativity Graph 2
Electronegativity
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0
2
4
Element
6
8
What trend(s)
do
you notice?
Electronegativity Trends
Electronegativity
Key Point #2: Electronegativity
increases as you go up the
periodic table and to the right
across the periodic table.
Practice Problems
• Rank the following elements in order
of increasing electronegativity based
on location on the periodic table
(smallest to biggest)
Mg, Sr, Be, Ra
Cl, Si, Al, S, P
Radon, Strontium, Magnesium, Beryllium
Aluminum, Silicon, Phosphorus, Sulfur, Chlorine
Practice Time!
1.
T or F? Electronegativity decreases as you move left across
the periodic table.
2. T or F? As you move down the Periodic Table, atoms get
more electronegative.
3. Rank the following sets of elements in order of increasing
electronegativity (small  big).
Set A: Bh, Mn, Re, Tc Set B: Sb, I, Ag, Ru
Set C: Y, Ti, Sg, Ta
4. Rank the following sets of elements in order of decreasing
electronegativity (big  small).
Set A: Cl, At, I, F, Br Set B: Te, Xe, Sn, In
Set C: Rb, K, Sr, Ca
How does atomic size related to
electronegativity?
Key Point #3: Atomic size is
indirectly related to
electronegativity.
ATOMIC SIZE
As electronegativity
ELECTRONEGATIVITY increases, atomic size
decreases!
Why is this relationship true?
• Atoms with HIGH
ELECTRONEGATIVITIES hold their
electrons very close!
• Sooooo, the atomic size decreases
High or low electronegativity?
Large or small atomic size?
Ionization Energy
• The energy required to remove 1 electron
from an atom
What do you think is the
relationship between ionization
energy and electronegativity?
What do you think is the
relationship between ionization
energy and electronegativity?
• The more an atom wants an electron
(electronegativity) the more energy it will
take to remove that electron (ionization
energy)
• So same pattern!!!
Ionization energy
Key Point #3: Ionization energy
increases as you go up the
periodic table and to the right
across the periodic table.
Electron Affinity
Very similar to other 2
How much an atom likes
electrons
Key Point #4: electron affinity
increases as you go up the
periodic table and to the right
across the periodic table.
Done early?
• Start review sheet!!!
Exit Slip
1. What are the 3 atomic trends we
studied?
2. How does each increase across the
periodic table
•
HW:
– Unit 4 review sheet
•
Top Ten: how’d we do?