Periodicity

Question 1

Why are elements classified in blocks s, p, d, f ?

Answer 1

Easy to read electronic configuration

Question 2

Trend in Atomic Radius across Period 3

Answer 2

Atomic Radius decreases- positive charge increases and electrons are pulled in closer to the nucleus, electron shielding remains the same

Question 3

First Ionisation Energy across Period 3

Answer 3

Ionisation energy increases - increasing attraction between outer shell electrons and nucleus, requiring it more energy to remove

Question 4

Trends of MP and BP for Na, Mg, Al

Answer 4

MP and BP increases , have a** giant metallic structure, strength of metallic bond increases** as the charge of the ion increases- more electrons join the delocalised sea

Question 5

Trends of MP and BP for Si, P, S, Cl

Answer 5

Silicon is a macromolecule and has the highest MP of P3, due to strong covalent bonds which require a lot of energy to break. P, S, Cl are simple molecules which have van der waals forces between molecules.

Question 6

MP of Argon

Answer 6

Argon has a very low melting point since it is monoatomic- weak van der waals forces.

Question 7

Why is Aluminium an exception to the ionisation energy trend?

Answer 7

Aluminium outer electron lies in the 3p orbital which is a higher energy level- further from the nucleus

Question 8

Why is Sulfur an exception to the ionisation energy trend?

Answer 8

Sulfur’s outer electrons are spin-paired, creating electron repulsion, making it easier to remove the electron