Flashcards
Ionisation Energy
Cards in this deck (8)
- 1DEFINE 1st Ionisation Energythe energy required for the removal of one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions
- 2What is the trend shown in successive ionisation energies? Explain this trend. (4)Each successive ionisation energy is higher than the previous one.
As each electron is removed, there is less repulsion between the remaining electrons and each shell will be drawn slightly closer to the nucleus.
As the distance of each electron from the nucleus decreases, the nuclear attraction increases.
This means more energy is required to remove the next electron from the outer shell. - 3What is the trend shown in 1st ionisation energies moving down a group? Explain this trend. (4)1st ionisation energies decrease.
The shielding increases (less energy needed).
The atomic radius increases (more distance, less energy needed).
The change in nuclear charge is outweighed by these factors. - 4What is the trend shown in 1st ionisation energies moving across a period? Explain this trend. (4)1st ionisation energy increases.
The atomic radius decreases (attraction between added electrons and nucleus draws the shells closer to the nucleus).
The nuclear charge increases (nuclear attraction is greater, more energy needed).
Change in shielding is negligible and outweighed by other factors. - 5Explain the drop in 1st ionisation energies Be→B and Mg→Al. (2)The next electron to be added to the shells of Be and Mg will go into the 2p and 3p orbitals.
This increase in shielding makes this electron easier to remove, decreasing the 1st ionisation energy. - 6Explain the drop in 1st ionisation energies N→O and P→S. (2)The next electron to be added to the shells of N and P will pair up to one of the 2p and 3p electrons.
The mutual repulsion between these electrons sharing an orbital means less energy is required to remove one of them, decreasing the 1st ionisation energy. - 7How do successive ionisation energies show evidence for shells? (2)Large jumps between successive ionisation energies show that all the outer shell electrons have been removed, and the next electron removed is from the next shell in.
This is shown as an larger increase in ionisation energy because the nuclear distance is lesser and the nuclear attraction is greater. - 8Write equations to show the first and second ionisation energies of lithium.Li (g) → Li+ (g) + e-
Li+ (g) → Li 2+ (g) + e-
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- A-Level Chemistry (3.1 The Periodic Table) Flashcards on Ionisation Energy, created by Sofia Ward on 20/04/2017.
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- Sofia Ward
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