Chemistry 0620 · IGCSE · Ions and ionic bonds

Ions and ionic bonds — practice question

Potassium and chlorine combine to produce potassium chloride, KCl.
(a)[2]

Write the equation for this reaction using chemical symbols.

(b)[3]

Complete the diagram so that it shows the outer-shell electron arrangement of the ions found in potassium chloride. Include the charges on both ions.

(c(i))[2]

State the meaning of electrolysis.

(c(ii))[2]

Name the products formed at the positive electrode (anode) and negative electrode (cathode) during electrolysis of molten potassium chloride.

(d(i))[2]

Write an ionic half-equation for the reaction at the negative electrode (cathode).

(d(ii))[1]

Name the product formed at the positive electrode (anode).

(d(iii))[1]

Name the potassium compound left in solution after electrolysis.

(e)[1]

Complete the dot-and-cross diagram to display the outer-shell electron arrangement in a chlorine molecule, Cl$_2$. Show only the outer electrons.

(f(i))[2]

Deduce the physical state of chlorine at -75$^\circ$C. Use the table data to justify your answer.

(f(ii))[3]

Explain, in terms of structure and bonding, why potassium chloride has a much higher melting point than chlorine. Your answer should mention the particles held by the forces of attraction, the kinds of attraction between particles, and how strong those forces are compared with each other.

Worked solution & mark scheme

This 19-mark question has a full step-by-step worked solution and mark scheme. One marking point: 2K + Cl₂ → 2KCl

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