Periodicity

Question 1

Describe trend in ionisation energy in period 3

Answer 1

Increase in i.e

increases nuclear charge = greater attraction between the nucleus

Question 2

What do the dips in the ionisation energy in period 3 mean?

Answer 2

fall at Al = 3p electron more away than 3s

fall at sulphur = repulsion between two electrons in the same orbital

Question 3

Describe the trend in atomic radius in period 3

Answer 3

• Decreases
• Increases nuclear charge
• greater attraction

Question 4

Describe trend in melting and boiling points across period 3

Answer 4

• Na, Mg + Al metals = increase in greater charged ions; electrostatic forces (metallic bonding)
• Silicon = macromolecular; strong covalent structure; require a lot of energy
• P,S+C = simple covalent molecules; weak van de waals; do not require much energy