CHAPTER 7 & 8 FLASHCARDS

Question 2

First ionisation energy

Answer 2

The energy required to remove 1 electron from 1 mole of atoms in the gaseous state to form 1 mole of gaseous +1 ions

Question 3

First ionisation energy half equation for Na

Answer 3

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

Question 4

What are the factors which affect ionisation energy?

Answer 4

Atomic radius, nuclear charge, electron shielding

Question 5

Why is helium’s second ionisation energy greater that its first?

Answer 5

In a helium atom there are 2 electrons and 2 protons. After the first electron is lost, the electron left over experiences a greater nuclear attraction to the helium nucleus so more ionisation energy will be required to remove the second electron.

Question 6

Second ionisation energy

Answer 6

Energy required to remove 1 electron from each ion in 1 mole of gaseous 1+ ions of an element to form 1 mole of gaseous 2+ ions.

Question 7

In a graph of successive ionisation energies, what do large jumps in ionisation energy indicate?

Answer 7

Marks a change from one shell to another which is closer to the nucleus and with less shielding

Question 8

What happens to first ionisation energy across a period?

Answer 8

Generally increases

Question 9

What happens to first ionisation energy between the end of one period and the start of the next period?

Answer 9

Sharp decrease

Question 10

What happens to first ionisation energies down a group?

Answer 10

Decrease

Question 11

Explain the trend in first ionisation energies down a group.

Answer 11

• First ionisation energy decreases
• Atomic radius increases
• More inner shells so shielding increases
• Nuclear attraction on outer shells decreases

Question 12

Explain the change in first ionisation energy across a period.

Answer 12

• First ionisation energy increases
• Nuclear charge increases
• Same shell so shielding stays the same
• Nuclear attraction increases
• Atomic radius decreases