Week 5 Flashcards
Ionisation Energy
the minimum energy required to remove an electron from a gaseous ground state atom or ion
Which electrons take less energy to remove?
Less energy to remove the first electron from the ground state atom
More energy to to remove the remaining electrons from the resulting ions
1st IE < 2nd IE
Less energy to remove the first electron
The electron-electron repulsion or electron shielding results in a weaker attraction of the nucleus for each electron
More energy to remove remaining electrons
When the first electron is removed, in the resulting cation there are fewer electrons present so there is less shielding and the electrons feel larger effect of the nuclear charge.
Periodic table trends for IE
Across a period- first IE increases
Down a group- first IE decreases
Type of element with highest first IE
Noble gases
Type of element with lowest first IE
Group one (alkali metals)
Size of atoms and cations
Cations are smaller than neutral atoms because cation’s valence shell is pulled towards the nucleus with greater effective nuclear charge
Size of atoms and anions
Anion is bigger than neutral atoms because anion’s valence shell is pulled towards nucleus with less effective nuclear charge
Reactivity of elements
Elements lose or gain electrons to complete the octet rule.
Noble gases- totally inert chemically. All have filled valence sub-shells, a condition that represents great stability.
Metals across the period
Across the period, IE increases due to greater core charge. As it increases, metals become less reactive as they lose electrons in chemical reactions
Metals down the group
Down the group, IE decreases and the metals become more reactive due to greater shielding effect
Non-metals across the period
Across the period, non-metals become more reactive because of increasing trend in electronegativity due to greater core charge
Non-metals down the group
Down the group, electronegativity decreases, due to greater shielding effect and non-metals become less reactive.
nth IE
removal of nth electron from gaseous ground +(n-1) cation