1/5/15 CHEMISTRY MRS.TURGEON

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• 1/5/15 CHEMISTRY MRS.TURGEON
• You create your own reality. - Jane Roberts
•  OBJECTIVES SWBAT
• 1. Identify 4 periodic trends on the periodic
  table
• DO NOW
• 1. What was your favorite thing about winter
  break?

2

• 1/9/15 CHEMISTRY MRS.TURGEON
• You create your own reality. - Jane Roberts
•  OBJECTIVES SWBAT
• 1. Identify if there is a periodic trend for
  density
• DO NOW
• 1. What does it mean to interpolate from a
  graph?

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• 1/9/15 CHEMISTRY MRS.TURGEON
•  REMINDERS
• If you want your science fair board, pick it up
  by today after school
• Homework finish lab analysis

4

• 1/9/15 CHEMISTRY MRS.TURGEON
• You create your own reality. - Jane Roberts
•  OBJECTIVES SWBAT
• 1. Identify if there is a periodic trend for
  density
• DO NOW
• 1. What does it mean to interpolate from a
  graph?

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Use a periodic table and your knowledge of the
element families to identify each element by
name.
1. I am a Noble Gas that is found in the 6th
period. 2. I am a member of the Alkaline Earth
family and have 88 electrons. 3. I am a
transition metal that is a liquid at room
temperature. 4. I am a member of the
miscellaneous carbon family that is found in the
5th period. 5. I am a Halogen that is a gas at
room temperature and have 3 energy levels.
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The answers are
1. I am a Noble Gas that is found in the 6th
period. 2. I am a member of the Alkaline Earth
family and have 88 electrons. 3. I am a
transition metal that is a liquid at room
temperature. 4. I am a member of the
Miscellaneous carbon family that is found in the
5th period. 5. I am a Halogen that is a gas at
room temperature and have 3 energy levels.
Radon
Radium
Mercury
Tin
Chlorine
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Periodic Trends

• In your groups
• What is the definition
• of a trend?

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Periodic Trends

• There are several important atomic
  characteristics that show predictable trends that
  you should know
• Atomic Size
• Ionization Energy
• Electron Affinity
• Electronegativity

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Atomic Size

• The bonding atomic radius is defined as one-half
  of the distance between bonded nuclei.

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Decreasing Atomic SizeAcross a Period

• The effect is that the more positive nucleus ()
  has a greater pull on the electron cloud (-)
• The increased attraction pulls the cloud in,
  making atoms smaller as we move from left to
  right across a period

Li
Be
B
1s22s1
1s22s2
1s22s22p1
Li
Be
B












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Increasing Atomic SizeDown a Group

• Electron Shielding When you add a significant
  number of electrons (to a higher energy level)
  the inner electrons start to shield the nucleus
  from the outer electrons

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Atomic Radii
1 2 13 14
15 16 17
13
0.3
Cs
Rb
0.25
K
0.2
Na
4d transition series
3d transition series
La
atomic radius
Li
0.15
Zn
Xe
Kr
0.1
Cl
F
0.05
He
H
0
0 10 20 30
40 50 60
atomic number
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Ionization Energy

• Amount of energy required to remove an electron
  from the ground state of a gaseous atom or ion.
• Given enough energy (in the form of a photon) an
  electron can leave the atom completely.
• The number of protons and electrons is no longer
  equal

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Ionization Energy

• Make a prediction in your groups
• As you move from left to right across a period,
  will ionization energy increase or decrease?

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Ionization Energy

• Generally, as one goes across a row, it gets
  harder to remove an electron.
• The larger the atom is, the easier its electrons
  are to remove.
• Ionization energy and atomic radius are inversely
  proportional

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Ionization Energies
INCREASES
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Group 1
Period
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Ions

• Here is a simple way to remember which is the
  cation and which the anion

This is Ann Ion.
This is a cat-ion.
Shes unhappy and negative.
Cats are paw-sitive
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Sizes of Ions

• Cations are smaller than their parent atoms.
• The outermost electron is removed and repulsions
  are reduced.

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Sizes of Ions

• Anions are larger than their parent atoms.
• Electrons are added and repulsions are increased.

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• 1/6/15 CHEMISTRY MRS.TURGEON
• We see things as we are, not as they are.
• 
  - Jane Roberts
•  OBJECTIVES SWBAT
• 1. Identify 4 periodic trends on the periodic
  table
• DO NOW
• 1. What is electron shielding? How does it
  affect atomic radius?

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Electron Affinity

• Electron affinity Love of electrons
• Energy change accompanying addition of electron
  to gaseous atom
• Cl e- ??? Cl-

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Electronegativity

• Electronegativity is a measure of an atoms
  attraction for another atoms electrons.
• Is directly related to Electron Affinity
• scale that ranges from 0 to 4.
• Fluorine is the most electronegative!!!!

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Electron Affinity Electronegativity
INCREASES
1A
8A

1
1
3A
5A
7A
2A
4A
6A
Li 1.0
2
2
Mg 1.2
3
3
4B
6B
1B
2B
3B
5B
7B
Period
Ca 1.0
Sc 1.3
4
4
Sr 1.0
Y 1.2
Zr 1.4
5
5
?
Hf 1.3
La 1.1
6
6
?
Ac 1.1
?
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Electronegativity
?
1.0 - 1.4
Lanthanides 1.1 - 1.3
Actinides 1.3 - 1.5
Hill, Petrucci, General Chemistry An Integrated
Approach 2nd Edition, page 373
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Periodic Trends

• Atomic Radii - size
• Ionization Energy energy change when
  losing an e-
• Electron Affinity - energy change when
  gaining an e-
• Electronegativity ability to attract e-
  when in a compound

Forms cation!
Forms anion!
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Periodic Trends

• Octet Rule atoms tend to gain, lose, or share
  electrons in order to acquire a full set of eight
  valence electrons
• As a group carefully read about the octet rule
  on pg. 193 in your textbook and make your own
  notes about this VERY important rule!

Forms cation!
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Summary of Periodic Trends
Atomic radius decreases Ionization energy
increases Electron affinity increases Electronegat
ivity increases
Atomic radius increases Ionization energy
decreases Electron Affinity decreases Electronegat
ivity decreases
1A
0
2A
3A
4A
6A
7A
5A
Ionic size (cations) Ionic size
(anions)? decreases decreases
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• What ion will be formed when K loses 1 e-?
• K1 (cation)
• What ion will be formed when O gains 2 e-?
• O2- (anion)
• Which ion above is more electronegative?
• O2- (anion)