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Element X has an atomic radius that is smaller than that of sulfur - VCE - SSCE Chemistry - Question 14 - 2005 - Paper 1
Question 14
Element X has an atomic radius that is smaller than that of sulfur. In chemical reactions, element X commonly forms an ion that has the same electron configuration a... show full transcript
Worked Solution & Example Answer:Element X has an atomic radius that is smaller than that of sulfur - VCE - SSCE Chemistry - Question 14 - 2005 - Paper 1
Step 1
Identify Element X
Answer
To determine which element X could be, we need to compare the atomic radii of the options given: oxygen, chlorine, argon, and potassium with that of sulfur.
Oxygen has a smaller atomic radius than both sulfur and chlorine. Chlorine is a non-metal with a larger atomic radius than sulfur. Argon, being a noble gas, has a larger atomic radius than sulfur, and potassium has a significantly larger radius due to being an alkali metal.
Hence, oxygen is a valid candidate for element X as it is smaller than sulfur.
Step 2
Evaluate Ion Configuration
Answer
Element X also needs to be capable of forming an ion with the same electron configuration as Se^2+. Since Se^2+ means that sulfur gained two electrons, we look for an element that can lose or form ions similarly.
Oxygen typically forms O^2- ions, which achieves a noble gas configuration similar to Se^2+.
Thus, the best choice among the listed options is:
C. argon.
All others do not match the criteria of atomic radius and electron configuration.