F321-Ionisation Energies

Question 0

Where is the first electron removed from in the atom and why?

Answer 0

It’s removed from the outer shell- because the electron on the outer she’ll has the least nuclear attraction so has a higher ionisation energy

Question 1

Is a cation positively or negatively charged?

Answer 1

Positively

Question 2

Define first ionisation energy

Answer 2

The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions. Units are kJmol-1

Question 3

Represent the first ionisation energy of sodium

Answer 3

Na(g) > Na+(g) + e-

Question 4

What 4 factors is the energy required to remove an electron dependent on?

Answer 4

-nuclear charge
-distance from the nucleus to the outer electron (atomic radius)
-shielding of outer electron
~nuclear attraction on outer electron

Question 5

Describe the trend of ionisation energy across a period

Answer 5

• nuclear charge increases
• same number of shells so same shielding of outer electron
• atomic radius decreases so less distance from nucleus to outer electron
• nuclear attraction on outermost electron increases so first ionisation energies increase.

Question 6

Describe the trend of ionisation energy down a group

Answer 6

• nuclear charge increases
• however, this is outweighed by more shells so more shielding of outer electron
• further distance from the nucleus to the outer electron
• weaker nuclear attraction on outermost electron so first ionisation energy decreases.

Question 7

Define successive ionisation energy

Answer 7

A measure of the energy required to remove each electron in turn

Question 8

Show the fourth ionisation energy of a copper atom

Answer 8

Cu3+(g) > Cu4+(g) + e-

Question 9

Why is the second ionisation energy of element X greater than the first ionisation energy?

Answer 9

• electrons are removed from the same shell
• less electrons results in less electron repulsion
• proton to electron ratio increases as each electron is removed
• remaining electrons experience more nuclear attraction
• more energy is needed to remove each electron in turn.

Question 10

What group on the periodic table does element X belong to?

Answer 10

• the largest increase in ionisation energy is between the 2nd and 3rd electron being removed
• the 3rd electron must have been removed from a new shell, closer to the nucleus, experiencing more nuclear attraction
• there must be two electrons in the outer shell
• element X must be in group 2

Question 11

On the graph of successive ionisation energies for atoms of elements, what does the first group of crosses represent?

Answer 11

How many electrons are on the outer shell

Question 12

What should you always do when comparing the first ionisation energies of two different elements?

Answer 12

Choose one element & bullet point the model answer. Conclude by including both elements In the final point

Question 13

Is an anion positively or negatively charged?

Answer 13

Negatively