Section 1 : Atomic structure - Ionisation Energy Flashcards
What is first ionisation energy?
First ionisation energy is the amount of energy needed to remove 1 electron from every atom in 1 mole of gaseous atoms to form 1 mole of gaseous ions.
What is second ionisation energy ?
Second ionisation energy is the amount of energy needed to remove 1 electron from every 1+ ion in 1 mole of gaseous 1+ ions to form to form 1 mole of gaseous 2+ ions.
Which 3 factors affect ionisation energy?
Nuclear charge
Atomic radius
Shielding
How does an increase in nuclear charge affect ionisation energy?
If nuclear charge increases then the nucleus is more positive , this means there is a stronger electrostatic force of attraction between the negative outer most electrons and the positive nucleus.
A greater nuclear charge means a greater ionisation energy is needed as more energy is needed to over come the electrostatic force of attraction between the nucleus and electron.
How does atomic radius affect ionisation energy ?
Electrons a greater distance from the nucleus require less energy to be removed hence as atomic radius increases ionisation energy decreases.
How does shielding affect ionisation energy?
An increase in shielding leads to a decrease in ionisation energy as there are weaker forms of attraction between the positive nucleus and negative outermost electrons.
How does removing 1 electron affect the ability to remove a consecutive electron?
Every time your remove an electron from an atom you create a progressively more positive ion. This means each successive ionisation energy becomes bigger as the positive charge in the middle holds onto each of its electrons more tightly after having lost one , these more tightly held electrons take more energy to remove.
How will ionisation energy change down a group?
Down a group ionisation energy will decrease , this is because both shielding and the atomic radius increase lessening the hold of the positive nucleus on the negative electrons. Even though the nuclear charge increases which normally would increase ionisation energy the , effects of increased shielding and atomic radius override this effect, decreasing ionisation energy down the group.
How will ionisation energy change across a period?
Ionisation energy increases across a period this is because shielding remains constant so has no effect, atomic radius gets smaller and the nuclear charge increases , therefore with progression across the period ionisation energy increases.
If there is a bug jump in the ionisation energy to remove two successive electrons what does it indicate?
It indicates you have began removing electrons from a different energy level (one closer to the nucleus).
In which order do shells fill starting with 1S ?
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
What can the number that dictates the energy level also be referred to as?
The principle quantum number.
