FC7 IE and Radii

Question 1

What is the first ionisation energy of an element

Answer 1

The energy needed to remove one electron from each atom in a mole of gaseous atoms of an element

Question 2

What is the equation for the first ionisation energy, including state symbols

Answer 2

X (g) -> X+(g) +e-

Question 3

What is the equation for the second ionisation energy, including state symbols

Answer 3

X+(g) -> X2+ (g) + e-

Question 4

What are the 3 factors that effect ionisation energies

Answer 4

• Nuclear charge
• Atomic radius
• Shielding effect

Question 5

When the nuclear charge is higher, what happens to the ionisation energy and why

Answer 5

It’s higher because there is greater attraction

Question 6

When the atomic radius is greater, what happens to the ionisation energy and why

Answer 6

Lower ionisation energy because the attraction is weaker between the nucleus and the outermost electrons

Question 7

Overall, going across a period what happens to the ionisation energy

Answer 7

It increases

Question 8

What happens to the ionisation energy going down a group, and why

Answer 8

It decreases because there is increased distance and shielding from the extra shells and these outweigh the increase in nuclear charge

Question 9

Between group 2 and group 3 elements going across the group the ionisation energy decreases, explain why

Answer 9

The highest energy electron is in the p-subshell for the group 3 element but in the s-subshell for the group 2 element. Since the p-subshell is at slightly higher energy than the s-subshell, it is slightly easier to remove the outer electron from the group 3 element

Question 10

Between group 5 and group 6 the ionisation energy decreases explain why

Answer 10

In the group 6 the highest energy electrons are in a pair so they repel whereas in group 5 they are unpaired so the repulsion raises their energy it’s slightly easier to remove an electron from group 6.

Question 11

Is the first ionisation energy higher or the second and explain why

Answer 11

The second, because there are fewer electrons so less repulsion and they get more strongly attracted to the nucleus.

Question 12

When there’s a big jump in ionisation energies, what does this indicate

Answer 12

That they are now taking electrons from a new shell that is closer to the nucleus so there is greater attraction