How ionic bonds form by transfer of electrons, dot-and-cross diagrams for ionic compounds, predicting whether a bond is ionic or covalent, and writing formulae for ions and ionic compounds.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Table salt is made of a metal that explodes in water and a poisonous gas. Transferring electrons turns them into a stable, edible crystal.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Rotate the crystal and find the ions around one sodium ion.
Copy these into your notebook in your own words — that is how they stick.
Positive ion (metal atom lost electrons); negative ion (non-metal atom gained electrons).
Electrostatic attraction between oppositely charged ions formed by electron transfer.
Outer shells only; brackets and charges; one symbol per atom.
Total positive charge = total negative charge.
Ratio of ions in the lattice, e.g. MgCl₂.
Group I 1+, Group II 2+, Al 3+; Group VII 1−, Group VI 2−.
Charge of one ion becomes subscript of the other.
Metal + non-metal → ionic; two non-metals → covalent.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Chemistry Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
Magnesium (atomic number 12) reacts with oxygen (atomic number 8) to form magnesium oxide.
(a) (a) Write the electron arrangement of a magnesium atom and an oxygen atom. [2]
(b) (b) Draw a dot-and-cross diagram for magnesium oxide, showing outer electrons only. [4]
(c) (c) Explain how the ionic bond is formed. [2]
(d) (d) Write the formulae of the compounds formed between: (i) sodium and chlorine, (ii) calcium and hydroxide, (iii) aluminium and sulfate. [3]
(e) (e) Write the formula of zinc chloride and explain why it is not ZnCl. [2]
(f) (f) Predict whether the compound formed between carbon and chlorine is ionic or covalent and give a reason. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.