New Unit Periodic Trends
New Unit
Periodic Trends
Background *Textbook Section 5-1 1) Mendeleev and Chemical Periodicity
2) Moseley and Nuclear Charge
3) The Periodic Law
*Understanding Periodic Trends starts with Coulombic Attraction In class we will check answers to worksheets completed in class. *More Periodic Table Geography In class you may have color coded a Periodic Table to show group/family names, etc. If you did not be sure include an image in your notes. You can use pages 130-131 in your text or any other you find online. For example: What group number are the Alkaline Earth metals?
The Periodic Trends We Will Study 1. Atomic Radius 2. Ionization Energy and Successive Ionization Energy 3. Electron Affinity 4. Electronegativity 5. Ionic Radius Our List of Goals for Each Trend A. Know the definition B. For main group elements state the trend across a period and explain why this trend occurs. C. For main group elements state the trend within a group and explain why this trend occurs D. Recognize that there are exceptions (think: d and f blocks) and be able to use electron configuration to discuss an explanation for why these exceptions occur.
#1 Atomic Radius Trend for Main Group Elements
#2 Ionization Energy Trend for Main Group Elements
Values are in kJ/mole
Successive Ionization Energies
Values are in kJ/mole The table above shows the energy required for removal of additional electrons from elements in the second period. What trends do you see? What is the significance of the gold shading?
#3 Electron Affinity Electron affinity is essentially the opposite of ionization energy. Instead of removing an electron from the element; an electron is added to form an anion. The negative sign indicates that energy is released. The more negative this energy value the more this process is favored. Trend for Main Group Elements
Values are in kJ/mole
1) What do you notice about this trend and the Noble gases, Alkali metals and Alkaline Earth metals (also called Alkali Earth metals)?
2) What do you notice about this trend and the Nonmetals especially the Halogens?
#4 Electronegativity A) Definition
Trends for Electronegativity Summarized in this table
Values use the Pauling scale. The Pauling scale is a numerical scale of electronegativities based on bond-energy calculations.
Sample Questions 1. State the Periodic Law.
2. Identify each element as a metal, metalloid, or nonmetal. a) fluorine b) germanium c) zinc d) phosphorous e) lithium
3. Give two examples of elements for each category. a) noble gases b) halogens c) alkali metals d) alkaline earth metals
4. What trend in atomic radius do you see as you go down a group/family on the periodic table?
What causes this trend?
5. Circle the atom in each pair that has the largest atomic radius. a) Al
B
d) Na Al
b) S O
c) Br Cl
e) O F
f) Mg Ca
6. a) Name the largest Alkaline Earth metal. b) Name the smallest element in the 3rd period.
Summary of All Periodic Trends
Periodic Trends
Background *Textbook Section 5-1 1) Mendeleev and Chemical Periodicity
2) Moseley and Nuclear Charge
3) The Periodic Law
*Understanding Periodic Trends starts with Coulombic Attraction In class we will check answers to worksheets completed in class. *More Periodic Table Geography In class you may have color coded a Periodic Table to show group/family names, etc. If you did not be sure include an image in your notes. You can use pages 130-131 in your text or any other you find online. For example: What group number are the Alkaline Earth metals?
The Periodic Trends We Will Study 1. Atomic Radius 2. Ionization Energy and Successive Ionization Energy 3. Electron Affinity 4. Electronegativity 5. Ionic Radius Our List of Goals for Each Trend A. Know the definition B. For main group elements state the trend across a period and explain why this trend occurs. C. For main group elements state the trend within a group and explain why this trend occurs D. Recognize that there are exceptions (think: d and f blocks) and be able to use electron configuration to discuss an explanation for why these exceptions occur.
#1 Atomic Radius Trend for Main Group Elements
#2 Ionization Energy Trend for Main Group Elements
Values are in kJ/mole
Successive Ionization Energies
Values are in kJ/mole The table above shows the energy required for removal of additional electrons from elements in the second period. What trends do you see? What is the significance of the gold shading?
#3 Electron Affinity Electron affinity is essentially the opposite of ionization energy. Instead of removing an electron from the element; an electron is added to form an anion. The negative sign indicates that energy is released. The more negative this energy value the more this process is favored. Trend for Main Group Elements
Values are in kJ/mole
1) What do you notice about this trend and the Noble gases, Alkali metals and Alkaline Earth metals (also called Alkali Earth metals)?
2) What do you notice about this trend and the Nonmetals especially the Halogens?
#4 Electronegativity A) Definition
Trends for Electronegativity Summarized in this table
Values use the Pauling scale. The Pauling scale is a numerical scale of electronegativities based on bond-energy calculations.
Sample Questions 1. State the Periodic Law.
2. Identify each element as a metal, metalloid, or nonmetal. a) fluorine b) germanium c) zinc d) phosphorous e) lithium
3. Give two examples of elements for each category. a) noble gases b) halogens c) alkali metals d) alkaline earth metals
4. What trend in atomic radius do you see as you go down a group/family on the periodic table?
What causes this trend?
5. Circle the atom in each pair that has the largest atomic radius. a) Al
B
d) Na Al
b) S O
c) Br Cl
e) O F
f) Mg Ca
6. a) Name the largest Alkaline Earth metal. b) Name the smallest element in the 3rd period.
Summary of All Periodic Trends
