08.E Annotated (1211K) Chemistry PDF

Tip of the Day Each time you review class material, keep track of your questions. Consider a dedicated “questions page” in a notebook or sticky notes on physical notes.  Chapter Eight The Quantum Model of the Atom CHEM 1211K 2 ...

Tip of the Day Each time you review class material, keep track of your questions. Consider a dedicated “questions page” in a notebook or sticky notes on physical notes.  Chapter Eight The Quantum Model of the Atom CHEM 1211K 2  Objectives At the end of this chapter you should be able to: 1. Describe and apply the dual nature of light. 2. Calculate energy, frequency, or wavelength of a sample of light. 3. Use the Bohr model of energy levels in atoms to explain light emission and absorption by gaseous atoms. 4. Calculate the energy or wavelength of a specific electronic transition in a hydrogen atom. 5. Use the concept of quantum numbers to characterize the energies, spatial distributions, and spins of atomic electrons. 6. Visualize and describe the spatial distributions and energies of atomic electrons using the quantum model of the atom. 7. Sketch the electronic energy levels of an atom. 8. Add electrons to atomic orbital energy (energy level) diagrams. 9. Determine electron configurations for the elements using the concepts of shells, subshells, and orbitals. 3  Orbital Diagrams (8.6) Electrons are represented by arrows pointing up or down, which represents the spin of the electron. 4  Orbital Diagrams (8.6) Aufbau principle (or building-up principle) Hund’s rule 5  In-Class Question 1 Consider a d subshell containing 7 electrons. How many unpaired electrons does this subshell contain? Learning Objective 8.7, 8.8  Electron Configurations (8.7) An electron configuration for an atom shows the particular orbitals that electrons occupy for that atom. 7  Orbital Diagrams (8.6) Energy-level diagrams – Orbitals within a subshell are degenerate - they have the same energy. – The relative energies of subshells can be determined from the periodic table. 8 Figure 8.20  Electron Configurations (8.7) For s and p block elements, n = row number For d block elements, n = row number – 1 For f block elements, n = row number – 2 9 Figure 8.25  Electron Configurations (8.7) Figure 8.21 Interactive: A workspace contains areas labeled orbitals, electrons, Lewis valence electron dot structure, orbital diagram, and electron configuration, and an area for building an atom that also contains an element from the periodic table. There are tabs labeled level 1 through 3 that change the element to be built. The orbital area contains the shapes of the 9 orbitals from 1 S to 3 P. The orbital diagram area contains an energy diagram with energy on the Y axis and boxes corresponding to the 9 orbitals in the orbitals area. There is a sphere in the electron area. The symbol of the element appears in the Lewis valence electron dot structure area. The electron configuration area is initially blank. Orbitals must be added in order from lower energy to higher energy. The 2 P X, 2 P Y, and 2 P Z orbitals have the same energy, and the 3 P X, 3 P Y, and 3 P Z orbitals have the same energy. Only two electrons can be placed in each orbital. One electron must be added to all orbitals with the same energy before the second electron can be added to that orbital. Example 1: Level 1. The atom to assemble is beryllium with an atomic number of 4. Drag the 1 S orbital to the central area. Place two electrons in the orbital. The electrons move around randomly in the orbital. Two arrows pointing in opposite directions appear in the 1 S box in the orbital diagram area. 1 S 2 appears in the electron configuration area. Drag the 2 S orbital to the central area. Place two electrons in the orbital. Two more arrows appear in the 2 S box in the orbital diagram area. The electron configuration changes to 1 S 2 2 S 2. Two dots appear around the B E symbol in the Lewis valence dot structure area. A box appears with the text you have assembled the atom correctly. Example 2: Level 1. Drag the 1 S orbital to the central area. Then drag the 2 S orbital to the central area. A box appears with the text you have violated the Aufbau principle. Electrons fill available orbitals with the least energy first. Each orbital can hold two electrons. Example 3: Level 1. Drag the 1 S orbital to the central area. Then place three electrons in the orbital. A box appears with the text you have violated the Pauli Exclusion Principle. Each orbital can hold a maximum of two electrons. Figure 8.27 Electron Arrangement App 10  In-Class Question 2 What is the highest energy occupied orbital in the ground state electron configuration for antimony (Sb)? Enter the subshell label, such as “1s” or “3p.” Learning Objective 8.8, 8.9  In-Class Question 3 How many of the electrons in the ground-state electron configuration for antimony (Sb) occupy s orbitals? Consider all shells! Learning Objective 8.8, 8.9  Electron Configurations (8.7) Abbreviated electron configuration Example: Write the abbreviated electron e–! configurations for calcium and scandium. 13  Electron Configurations (8.7) Core electrons – The inner electrons, which lie closer to the nucleus. Valence electrons – “Outer” electrons shown explicitly when a noble gas shorthand is used to write electronic configurations. 14  Electron Configurations (8.7) Cations Form when an atom loses one or more electrons. The most common cations of s- and p-block elements have noble gas electron configuration. 15  Electron Configurations (8.7) All atoms lose their highest energy electrons first to form cations. – For s- and p-block elements, these are the s- and p- electrons with the highest value of n. 16  Electron Configurations (8.7) Anions Formed when an atom gains one or more electrons. The most common anions of s- and p-block elements have noble gas electron configuration after ionization. All anions start as nonmetals 17  In-Class Question 4 How many unpaired electrons are in the ground state electron configuration for an iron atom? Learning Objective 8.8, 8.9  In-Class Question 5 How many unpaired electrons are in the ground state electron configuration for Fe3+? Enter your answer as a number. Learning Objective 8.8, 8.9  In-Class Question 6 An atom or ion has the abbreviated electron configuration [Kr]. Select the species that it could not possibly be. – A. Br B. K+ C. Sr2+ D. Rb+ E. Se2– Learning Objective 8.8, 8.9