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Unformatted text preview: guo (rg27533) Homework 3 Sutcliffe (52380) 1 This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Generally speaking, in the periodic table, elec- tronegativity (decreases, increases) in going from left to right and (decreases, increases) in going from bottom to top. 1. increases; increases correct 2. increases; decreases 3. decreases; decreases 4. decreases; increases Explanation: As the elements become less metallic their electronegativities increase. 002 10.0 points All of the following can have the ground-state electron configuration [Xe] 4 f 14 5 d 10 except 1. Tl + correct 2. Pb 4+ 3. Hg 2+ 4. Bi 5+ 5. Au + Explanation: Write the electron configurations for the ions listed to see which one matches the outer electron configuration given. The Aufbau or- der of electron filling is 1 s , 2 s , 2 p , 3 s , 3 p , 4 s , 3 d , 4 p , 5 s , 4 d , 5 p , 6 s , 4 f , 5 d , 6 p , etc . s orbitals can hold 2 electrons, p orbitals 6 electrons, and d orbitals 10 electrons. Note some exceptions do occur in the electron con- figuration of atoms (and ions) because of the stability of either a full or half-full outermost d-orbital, so you may need to account for this by shuffling an electron from the ( n- 1) s orbital. When electrons are removed from or- bitals in a neutral atom to create a positive ion they are taken in this order: outermost (highest value of n ) p , outermost s , then out- ermost d . 003 10.0 points Arrange the following ions in order of increas- ing radius: K + , Li + , Be 2+ , Na + . 1. Li + < Na + < K + < Be 2+ 2. K + < Be 2+ < Li + < Na + 3. Na + < K + < Be 2+ < Li + 4. Be 2+ < Li + < Na + < K + correct Explanation: Ionic radius decreases with atomic number in a given set of isoelectronic species, thus Be 2+ is smaller than Li + . Ionic radius in- creases down a given family on the periodic table, thus Li + is smaller than Na + , which is in turn smaller than K + . 004 10.0 points F- is bigger than F because 1. F- has one more electron which causes greater electron repulsions in the outer or- bitals, thus expanding the electron cloud. correct 2. F- has one more electron so there is less effective shielding of the nuclear charge. 3. F- has one less electron so there is more effective shielding of the nuclear charge. 4. F- has one more electron which causes less electron repulsions in the outer orbitals, thus expanding the electron cloud....
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