Trends in Ionisation Energy (Leaving Cert Chemistry): Flashcards
📚Flashcards
Practise the cards
13 cards from this deck
ShowHide
Practise the cards
13 cards from this deck
First ionisation energy definition
First ionisation energy definition
Min. energy to remove most loosely bound from neutral gaseous atom
Why measure IE for gaseous atoms only?
Why measure IE for gaseous atoms only?
Eliminates intermolecular forces; shows true nucleus- force
IE trend down a group
IE trend down a group
Decreases
Why IE decreases down group (distance factor)
Why IE decreases down group (distance factor)
Larger atomic radius = weaker attraction to nucleus
Screening effect on IE
Screening effect on IE
Inner shield outer from nucleus, lowering IE
IE trend across a period
IE trend across a period
Generally increases
Why IE increases across a period
Why IE increases across a period
Higher nuclear charge; in same shell = stronger attraction
Filled/half-filled sublevel effect on IE
Filled/half-filled sublevel effect on IE
Extra stability = higher IE than expected
Elements with unexpected high IE (exceptions)
Elements with unexpected high IE (exceptions)
Beryllium (filled 2s) & nitrogen (half-filled 2p)
Successive IE provide evidence for
Successive IE provide evidence for
Electron energy levels/shells
Large jump in successive IE indicates
Large jump in successive IE indicates
removed from inner energy level
Reactivity of low IE elements
Reactivity of low IE elements
Highly reactive (e.g., alkali metals)
Sodium first ionisation energy
Sodium first ionisation energy
kJ mol