Chemistry 0620 · IGCSE · Simple molecules and covalent bonds

Simple molecules and covalent bonds — practice question

Seven gases are listed below. ammonia ethene helium hydrogen hydrogen chloride methane nitrogen
(a(i))[1]

produces an acidic solution in water

(a(ii))[1]

is monatomic

(a(iii))[1]

makes up 78% of clean dry air

(a(iv))[1]

is the principal component of natural gas

(a(v))[1]

contains 14 protons in each molecule.

(b(i))[1]

State the names of any two elements in the list.

(b(ii))[1]

What does the term element mean?

(c)[2]

Complete the dot-and-cross diagram so that it shows the electron arrangement in a molecule of hydrogen chloride. Show outer electrons only. The diagram has overlapping circles labelled H and Cl.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: hydrogen chloride or HCl

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