7.2 ionisation energies module 3

Question 1

define ionisation energy

Answer 1

measures how easily an atom loses electrons to form positive ions

Question 2

define first ionisation energy

Answer 2

the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions

Question 3

what happens when electrons are taken from a closer shell to the nucleus?

Answer 3

large increase in ionisation energy
less shielding
more attraction between nucleus and electrons
smaller atomic radius

Question 4

what is the trend in first ionisation energy down a group?

Answer 4

decreases down a group
atomic radius increases
more inner shells so shielding increases
nuclear attraction on outer electron decreases

Question 5

how does atomic radius affect ionisation energy?

Answer 5

larger the distance, less nuclear attraction

Question 6

how does nuclear charge affect ionisation energy?

Answer 6

more protons there are, greater the attraction between the nucleus and the outer electrons

Question 7

how does electron shielding affect ionisation energy?

Answer 7

inner-shell electrons repel outer shell electrons, reduces attraction between nucleus and outer electrons

Question 8

what is the trend in first ionisation energy across a period?

Answer 8

nuclear charge increases
nuclear attraction increases
atomic radius decreases
first ionisation energy increases

Question 9

why is the first ionisation energy of boron lower than beryllium?

Answer 9

2p sub-shell in boron has a higher energy than the 2s sub-shell in beryllium
2p electron is easier to remove than one of the 2s electrons in beryllium

Question 10

why is the first ionisation energy of oxygen lower than nitrogen?

Answer 10

oxygen has paired electrons in one of the 2p orbitals which repel each other making it easier to remove

Question 11

first ionisation energy equation

Answer 11

X(g) —-> X+ + e-