Ionisation Energy (AQA A-Level Chemistry): Flashcards

Energy required to remove an electron from an atom or ion

Energy to remove 1 mol e⁻ from 1 mol gas atoms → 1 mol +1 ions

kJ/mol (kilojoules per mole)

$X(g) \rightarrow X^+(g) + e^-$

Energy needed to remove more than one electron from an atom

Electron removed is closer to the nucleus

Fewer electrons to shield attraction from nucleus

Always higher than the previous one

$X^+(g) \rightarrow X^{2+}(g) + e^-$

$X^{2+}(g) \rightarrow X^{3+}(g) + e^-$