Chemistry
Chapter 7: 5-6
Homework
Periodic Trends due to Electron Configurations
Chapter 7: 5-6 Homework
- Reading Preparation
- WebLecture
- Study Activity
- Preparation work for chat
- Online Quiz
- Lab Instructions
Reading Preparation
Textbook assignment: Read Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 7: Sections 5-6.
Study Notes
7.5 Periodic Trends: Electron configurations determine the size, ionization energy, and electron affinity of each element and its ions. Since the periodic table arranges elements according to their configurations as well as their proton count, the table shows trends in these characteristics.
- Size increases as we go down a group, but decreases as we move across a period.
- Ionization energy decreases as we go down a group, but increases as we move across a period.
- Electron affinity decreases as we go down a group, and generally increases as we move across a period, but decreases when we move to a new orbital shape.
7.6 Chemical Properties: Ionization energy gives clues as to what kinds of molecular bonding a particular element or ion can achieve by losing one or more electrons; electron affinity shows us what kinds of bonding is most likely to occur when an atom adds an electron to its configuration. Remember that in either case, minimal energy input or maximal energy release is most likely to achieve a more stable configuration.
There are no equations for these sections.
Web Lecture
Read the following weblecture before chat: Periodic Trends
Study Activity
Videos for Chapter 7: Electron Configurations
Review the Videos at Thinkwell Video Lessons.
- Under "Electron Configurations and Periodicity: Electron Spin and the Pauli Exclusion Principle"
- Periodic relationships
- Under "Electron Configurations and Periodicity: Periodicity"
- Periods and Atomic Size
- Ionization Energy
- Electron Affinity
- An Introduction to Electronegativity
Use the AACT Interactive Periodic Table: Periodic Trends webpage to experiment with how atomic and ionic radii differ for different elements.
- Compare the radius of a lithium atom with the lithium ion Li+1. Note the ionization energy.
- Compare the radius of a magnesium atom with the magnseium ion Mg+1. Note the ionization energy.
- Compare the radius of a magnesium atom with the magnseium ion Mg+2. Note the ionization energy.
- Use the graphs to compare the radius of magnesium and lithium with other elements in their periods.
- Reset the display, select sodium (Na) for the first atom and then click your way across the period from magnesium to argon. What happens to the atomic radius as the number of electrons increases? Why?
- Reset the display, select Beryllium (Be) for the first atom and then click your way down the group from magneisum to barium. What happens to the atomic radius as the atomic number and electrons increase? Why? How large are the first two levels in beryllium compared to the same levels in barium? Why?
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
Chapter Quiz
- Required: Complete the Mastery exercise with a passing score of 85% or better.
- Go to the Moodle and take the quiz for this chapter.
Lab Work
LAB #5 GUIDED INQUIRY: Using two-phase chromatography separation of mixtures -- Phase III
Create a formal report following the report format outlined in the SO Chemistry Student Guide. If you followed the procedure in one of the references below and answered questions as part of that procedure, include these in your report.
References:
- AP2009 18 Separation by Chromatography
- APGIE Investigation 5 Sticky Question: How Do You Separate Molecules that Are Attracted to One Another?
- IGHCE Lab 6.5 Chromatography: Two-Phase Separation of Mixtures
- HSCKM I-2 Chromatography
- Alternative Lab: Chromatography
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