Chemistry 5070 · O Level · Transition elements

Transition elements — practice question

Chromium belongs to the transition elements. Sodium is an element in Group I of the Periodic Table.
(a)[1]

Explain how chromium and sodium both conduct electricity.

(b)[2]

Describe two ways in which the physical properties of chromium and sodium differ.

(c)[2]

An alloy containing iron and chromium is stronger than pure iron. Use ideas about the structure of metals to explain why the alloy is stronger.

(d)[1]

Molten chromium reacts with steam to make chromium(III) oxide, $\text{Cr}_2\text{O}_3$, and hydrogen. Construct the equation for this reaction.

(e)[1]

A structure of a chromium-containing ion is shown. Write the formula for this ion.

(f(i))[2]

Adding dilute acid to yellow $\text{CrO}_4^{2-}(aq)$ produces orange $\text{Cr}_2\text{O}_7^{2-}(aq)$. Describe and explain what you would see when a few drops of concentrated aqueous sodium hydroxide are added to the orange solution.

(f(ii))[1]

Suggest why a change in pressure has no effect on the reaction shown.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Delocalised electrons pass through the metal structure

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