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Unformatted text preview: arriaga (yga77) – HW02 – quy – (50970) 1 This printout should have 34 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 3) 10.0 points What is the principal quantum number for the orbital 4 d ? 1. 6 2. 4 correct 3. 2 4. 5 5. 3 6. None of these Explanation: n = 4 002 (part 2 of 3) 10.0 points What is the orbital angular momentum quan tum number for the orbital 4 d ? 1. 1 2. 3 3. None of these 4. 5. 2 correct 6. 4 Explanation: ℓ = 2 003 (part 3 of 3) 10.0 points How many magnetic quantum numbers does the orbital 4 d have? 1. 3 2. 5 correct 3. None of these 4. 7 5. 1 6. 9 Explanation: m ℓ = 2 , 1 , , 1 , 2 004 10.0 points How many total nodal planes are present in the complete set of 3 d orbitals? 1. 20 2. 8 correct 3. 16 4. 3 5. 10 6. 5 Explanation: There are 5 orbitals in the 3 d set. 4 of those orbitals are cloverleafshaped and have 2 nodal planes each. That combines to give 8 total nodal planes for the set. The other (5th) orbital is the d z 2 orbital which has 2 nodal cones, not planes. 005 10.0 points How many nodes are present in a 3 s and a 3 p orbital, respectively? 1. 0 and 2 2. 0 and 1 3. 2 and 1 4. 2 and 2 correct 5. 1 and 1 arriaga (yga77) – HW02 – quy – (50970) 2 Explanation: A node is a point, a plane or a three dimen sional region of space where the sign of the wavefunction changes from positive to nega tive, (or negative to positive) so it equals zero. The lowest energy s orbital is 1 s , and this has no nodes – the wavefunction is always posi tive. As we go to the next higher value of n we add a spherical node, so 2 s would have one node, and 3 s two. The lowest energy p or bital is 2 p ; it has one nodal plane which cuts through the nucleus (the two ’lobes’ have op posite signs). Again, as we go to the next higher value of n we add a spherical node, so a 3 p orbital has two nodes. 006 10.0 points The transition metals are elements with par tially filled 1. s subshells. 2. d subshells. correct 3. p subshells. 4. f subshells. Explanation: In transition metals, d orbitals are being filled. 007 10.0 points An element with 20 protons and 20 electrons gains one electron. The electron goes into what type of orbital? 1. 4 p 2. 3 d correct 3. 3 p 4. 4 d 5. 3 s 6. 4 s Explanation: This element has electron configuration [Ar] 4 s 2 . The next electron goes into the 3 d orbital according to the Aufbau principle. 008 10.0 points Which element is predicted to have the groundstate electron configuration [He] 2 s 2 2 p 2 ? 1. nitrogen 2. oxygen 3. beryllium 4. hydrogen 5. helium 6. fluorine 7. carbon correct 8. neon 9. lithium 10. boron Explanation: Remembering the noble gas shorthand, count all of the superscripts that appear in the electron configuration. This will give the number of electrons which in a neutral atom is equal to the number of protons (atomic number of the element). Note some excep tions do occur in the electron configuration of...
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 Spring '08
 wandelt
 Atom, Periodic Table, Atomic orbital

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