3-Periodic Table and Energy

Question 1

Periodicity

Answer 1

the repeating trend in properties of the elements across a period

Question 2

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

Factors affecting ionisation

Answer 3

Atomic radius - the greater the distance between the nucleus and the outer shell the less the nuclear attraction, so much lower ionisation energy

Nuclear charge - more protons in the nucleus the greater the attraction between nucleus and outer electrons, so higher ionisation energy

Electron shielding - inner-shell electrons repel outer shell electrons which reduces the attraction between the nucleus and outer electrons.

Question 4

Trend in first ionisation energy across a period

Answer 4

General increase in first ionisation energy; nuclear charge increases, shell stays the same, so nuclear attraction increase, atomic radius decreases and so the first ionisation energy increases

A sharp decrease between the end of one period and the start of the next period; increased shell number so larger atomic radius and more shielding

Question 5

Trend in first ionisation energy down a group

Answer 5

Decrease down a group; the nuclear charge increases but the effect is outweighed by the increased radius and the increased shielding