This mini-lesson covers Structure 3.1: how the periodic table is organised and the periodic trends in atomic radius, ionisation energy, electronegativity and reactivity. This HL lesson also builds in the Additional Higher Level (AHL) material.
Work through each screen, answer the questions as you go (some are wordy, some are calculations) and collect ⭐ stars. Press Start when you're ready.
Elements are arranged by increasing atomic number.
So an element's position tells you its electron configuration, and vice versa.
Across a period the radius decreases: the nuclear charge rises but electrons enter the same shell, so the stronger pull draws them in.
Down a group the radius increases: each element adds a full shell, so outer electrons are further out and shielded.
The first ionisation energy is the energy to remove one mole of electrons from one mole of gaseous atoms.
The pattern of ionisation energies is direct evidence for electron shells.
Electronegativity increases across a period and decreases down a group, peaking near fluorine.
So metallic character decreases across a period (metals on the left, non-metals on the right) and increases down a group. Metal oxides tend to be basic; non-metal oxides tend to be acidic.
Group 1 (alkali metals): reactivity increases down the group — the outer electron is lost more easily.
Group 17 (halogens): reactivity decreases down the group — it is harder to gain an electron as atoms get bigger.
Transition elements have partly filled d sub-shells, giving variable oxidation states, coloured compounds (from d–d electron transitions) and useful catalytic behaviour. They also form complex ions with ligands.
Tap a trend, then how it changes.
Tap an item on the left, then its match on the right.
Layout: period = number of shells; group = valence electrons; s/p/d blocks
Across a period: radius ↓, ionisation energy ↑, electronegativity ↑
Down a group: radius ↑, ionisation energy ↓
Reactivity: group 1 ↑ down; group 17 ↓ down; metal oxides basic, non-metal oxides acidic
You've covered The periodic table and periodicity for IB Diploma Chemistry HL. Press Finish to see your score.
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