2002 年

The electronic diagram of an atom of element X is shown below:

(Only electrons in the outermost shell are shown.) The atomic number of X is probably

Which of the following compounds, when dissolved in water, gives a green solution?

An oxide of element X has the formula X₂O₃. 10.2 g of this oxide contains 5.4 g of X. What is the relative atomic mass of X ? (Relative atomic mass: O = 16.0)

Compound X dissolves in water to give a colourless solution. When chlorine gas is bubbled into the solution, the solution turns brown. X is probably

Sodium chromate, Na₂CrO₄, dissolves in water to give a yellow solution. When dilute hydrochloric acid is added to the solution, the following reaction occurs: 2CrO₄²⁻(aq) + 2H⁺(aq) → Cr₂O₇²⁻(aq) + H₂O(l) Which of the following statements concerning this reaction is correct ?

Which of the following statements concerning aluminium is correct ?

Which of the following equations represents a cracking reaction?

Consider the set-up below:

Electrons flow from X to Y in the external circuit. Which of the following combinations is correct ?

Which of the following reactions does NOT require the use of a catalyst?