Which statement about iodide ions, I−\text{I}^-I−, is correct?
They form a cream precipitate when reacted with acidified silver nitrate solution.
They have the electron configuration 1s22s22p63s23p63d104s24p64d105s25p51s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^51s22s22p63s23p63d104s24p64d105s25p5.
They reduce the sulfur in concentrated sulfuric acid to an oxidation state of −2-2−2.
They form a precipitate with silver nitrate that is soluble in concentrated aqueous ammonia.
37 exam-style questions on AQA A Level Chemistry Group 7(17), the halogens, covering Trends in properties and Uses of chlorine and chlorate(I). Each one has a worked solution and a mark scheme showing where the marks go.