Chemical Reactions and the Periodic Table
MYP Sciences Year 2 – Chemical Reactions and the Periodic Table
Everything in this unit boils down to one habit examiners are testing: can you connect an element's position in the periodic table to how it actually behaves? A metal near the top-left of the reactivity series doesn't just 'react a lot' — it loses electrons more easily, which is why it fizzes harder in acid, rusts faster outdoors, and gets chosen (or rejected) for a specific job. Every worked example below is built from real exam-style data tables, bar graphs and STSE scenarios, because that's exactly the format you'll be marked on.
Overview
Why metals behave the way they do
A chemical reaction is atoms rearranging to make something new. How eagerly an element does that rearranging depends on where it sits in the periodic table: metals want to lose electrons, non-metals want to gain them, and the reactivity series is simply a ranking of how strong that 'want' is.
- Sort elements into metals and non-metals using physical properties.
- Use the periodic table's groups and periods to predict behaviour.
- Rank metals with the reactivity series (acid, water, oxygen tests).
- Spot reactivity at work in rusting, cooking, batteries and material choice.
- Classify reactions as synthesis, decomposition, displacement or combustion.
- Recognise the observable signs that a chemical change has actually happened.
The shape of the chapter
Command terms this topic loves
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| Identify | Name or select the fact directly from the data given — no explanation required. | AO1 | 1 mark for the correct name/value; adding explanation earns nothing and wastes time. |
| Explain | State what happens AND give the reason (electron transfer, particle behaviour, etc.). | AO2 | The mark sits in the 'because' clause — a bare description without a mechanism scores zero on this part. |
| Compare | Give a similarity AND a difference, referencing BOTH items named, using a linking word. | AO3 | Two separate descriptions with no 'whereas/but/while' link score zero even if both facts are correct. |
| Justify | Give a reason for a choice, supported by the specific data/property in the question. | AO3 | A generic reason not tied to the actual numbers/properties given loses the mark. |
| Discuss / Evaluate | Weigh up more than one side (e.g. economic vs environmental) and reach a stated conclusion. | AO4 | One-sided answers, even if accurate, are capped at roughly half marks. |
Key point
Overview