Chromium is a transition element, whereas sodium is an element in Group I of the Periodic Table. State two physical properties of chromium that are unlike those of sodium.
Work out the number of protons and neutrons in the chromium atom shown, $^{53}_{24}\text{Cr}$.
Chromium(III) oxide, $\text{Cr}_2\text{O}_3$, reacts with carbon and chlorine to form chromium(III) chloride, $\text{CrCl}_3$, and carbon monoxide. Write the symbol equation for this reaction.
Complete the diagram in Fig. 2.1 so that it shows the electronic configuration of a sodium ion. Show the charge on the ion too.
Arrange the four metals by reactivity, starting with the least reactive one.
Explain why aluminium resists corrosion.
State two further reasons why aluminium is chosen for overhead electrical cables.