Periodicity

Question 1

What’s the trend in boiling point across Period 3. Why?

Answer 1

The boiling point Increases
more e- in the outer shell which are delocalised
atomic radii gets smaller with a higher atomic charge -makes bonds stronger

Question 2

Why is the boiling point of Si very high?

Answer 2

Forms a giant covalent lattice
more energy required to overcome strong bonds

Question 3

What do Cl,S,P form

Answer 3

Cl = Cl2 (g)
S = S8 (s)
P = P4 (s)

simple molecules which form week Van Der Waals interactions

Question 4

Why does Ar have the lowest boiling point in Period 3

Answer 4

Ar is Mon -atomic and simple molecular
fewer elections means fewer Van Der Waals forces so it’s weak

Question 5

Compare Br(-) and I(-)

Answer 5

Iodide ions are the strongest reducing agents of thr halide ions. This is because their outer electrons are further from the positive nucleus and experience more shielding. this makes it easier to donate electrons

Question 6

F block is made up of whay 2 groups

Answer 6

Lanthanides
Actinides

Question 7

What’s the trend in atomic radius across a period?

Answer 7

Atomic radius decreases across a period
number of protons increase, so does electrons
electrons are added to the same shell, so the radius doesn’t increase
due to the stronger attraction between the electrons and the nucleus, they are held closer