3.2: Trends in Size (Problems)
PROBLEM \(\PageIndex{1}\)
Based on their positions in the periodic table, predict which has the smallest atomic radius: Mg, Sr, Si, Cl, I.
- Answer
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Cl
PROBLEM \(\PageIndex{2}\)
Based on their positions in the periodic table, predict which has the largest atomic radius: Li, Rb, N, F, I.
- Answer
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Rb
PROBLEM \(\PageIndex{3}\)
Based on their positions in the periodic table, list the following atoms in order of increasing radius: Cs, Ca, Rb, Mg
- Answer
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Mg < Ca < Rb < Cs
PROBLEM \(\PageIndex{4}\)
Based on their positions in the periodic table, list the following atoms in order of increasing radius: Sr, Cl, Ca, Si.
- Answer
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Cl < Si < Ca < Sr
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PROBLEM \(\PageIndex{5}\)
Based on their positions in the periodic table, list the following ions in order of increasing radius: K + , Ca 2+ , Al 3+ , Si 4+ .
- Answer
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Si 4+ < Al 3+ < Ca 2+ < K +
PROBLEM \(\PageIndex{6}\)
List the following ions in order of increasing radius: Br – , Li + , Te 2– , Mg 2+ .
- Answer
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Li + < Mg 2 + < Br – < Te 2–
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PROBLEM \(\PageIndex{7}\)
Which atom and/or ion is (are) isoelectronic with Br + : Se 2+ , Se, As – , Kr, Ga 3+ , Cl – ?
- Answer
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Se, As −
PROBLEM \(\PageIndex{8}\)
Which of the following atoms and ions is (are) isoelectronic with S 2+ : Si 4+ , Cl 3+ , Ar, As 3+ , Si, Al 3+ ?
- Answer
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Si, Cl 3+
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PROBLEM \(\PageIndex{9}\)
Compare both the numbers of protons and electrons present in each to rank the following ions in order of increasing radius: As 3– , Br – , K + , Mg 2+ .
- Answer
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Mg 2+ < K + < Br – < As 3–
PROBLEM \(\PageIndex{10}\)
The ionic radii of the ions S 2– , Cl – , and K + are 184, 181, 138 pm respectively. Explain why these ions have different sizes even though they contain the same number of electrons.
- Answer
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They have different numbers of protons, which determines their size.
Contributors
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Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at http://cnx.org/contents/85abf193-2bd...a7ac8df6@9.110 ).
- Adelaide Clark, Oregon Institute of Technology