The Periodic Table：練習問題

Which statement correctly describes the arrangement of elements in the Periodic Table?

An unknown element is a hard metal with a high melting point. It forms a purple solution when its compounds are dissolved in water and it is often used as a catalyst in industrial processes. To which part of the Periodic Table does this element belong?

Aqueous bromine is added separately to test-tubes containing potassium chloride and potassium iodide solutions. Which statement correctly predicts the observations?

Across a period from left to right in the Periodic Table, how does the character of the elements change?

A student reacts an aqueous solution of potassium bromide, \(KBr(aq)\), with chlorine gas, \(Cl_2(g)\). What observation and conclusion can be made?

Group VII of the Periodic Table consists of the halogens. These elements show distinct trends in their physical and chemical properties.
(a) State the appearance (colour and state) of bromine at room temperature and pressure.
(b) A student adds aqueous chlorine to a test-tube containing potassium iodide solution. Describe the change in appearance of the solution and explain the reaction in terms of the reactivity of the halogens involved.
(c) Construct the word equation for the reaction described in part (b).