CAIE IGCSE Chemistry Ionic Properties from Structure and Bonding

Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise explaining ionic melting points and conductivity from electrostatic attraction in a lattice and the mobility of ions in different states.

How this is tested

link high melting and boiling points to strong attractions between oppositely charged ions
state that solid ionic compounds do not conduct because lattice ions cannot move
explain molten or aqueous conduction through mobile positive and negative charge carriers

[Maximum number: 2]

Sulfur is a Group VI element.

(a)

Sulfur reacts with magnesium to form magnesium sulfide, MgS, an ionic compound.

[ 2 ]

(i)

State why MgS has a high melting point.

[ 1 ]

(ii)

State why molten MgS conducts electricity.

[ 1 ]