Periodic Trends Direction
EN, IE, EA increase Right and Up (toward F); Atomic radius opposite
Electronegativity, ionization energy, and electron affinity all increase going right across a period and up a group. Atomic radius follows the opposite trend - increases left and down.
Breakdown
Electronegativity
Increases right and up (F = 4.0)
Ionization Energy
Increases right and up
Electron Affinity
Generally increases right and up
Atomic Radius
Opposite! Increases left and down
Metallic Character
Increases left and down
Remember
Most trends go toward fluorine!
Example
Comparing Na and Cl: Cl has higher EN (3.16 vs 0.93), higher IE, smaller radius, and is a nonmetal. Na has lower EN, larger radius, and is highly metallic.
When to Use This
- ✓Predicting element properties
- ✓Comparing elements in the same period or group
- ✓Explaining reactivity differences
- ✓Understanding bond polarity
FAQs
Common questions about this mnemonic
Going right: more protons increase effective nuclear charge, pulling electrons closer. Going up: fewer shells mean less shielding. Both increase attraction for electrons, causing higher EN/IE and smaller radius.
Noble gases have very high IE (full shells are stable) but electronegativity is often not reported because they rarely form bonds. Electron affinity is usually negative (unfavorable).