2.1 Periodicity

Question 1

Change in atomic radius along period

Answer 1

DECREASES
nuclear charge increases, same shielding
So greater electrostatic attraction to valence electrons

Question 2

Change in atomic radius down a period

Answer 2

INCREASES
Increase in quantum levels and greater shielding
So decreased electrostatic attraction to valence electron

Question 3

Ionisation energy across a period

Answer 3

INCREASES (except p1 and p4)
Greater nuclear charge for same shielding
P1- increase in orbital, valence electrons further
P4- electron pair repulsion

Question 4

Ionisation energy down a group

Answer 4

Increase in quantim level, increase shielding

Less E to overcome lower electrostatic attraction

Question 5

Electronegativity Change along period

Answer 5

INCREASES

Because greater nuclear charge for same shielding so greater electrostatic attraction to attract electron pair

Question 6

Electronegetivity change down a group

Answer 6

DECREASES
More quantum levels and greater shielding
Less electromagnetic attraction so can’t attract electron pair as easily

Question 7

PERIOD 3 BOILING POINT

Answer 7

Group 1 to 3- METTALIC BONDING, MORE DELOCALISES ELECTRONS so needs more energy to overcome electrostatic attraction
Group 4- MACROMOLECULAR lots lots of energy
Group 5-8- SIMPLE MOLECULAR, larger molecules have stronger vdw forces to overcome

Question 8

Electrical conductivity of Period 3

Answer 8

Group1-3 INCREASES, more delocalised electrons to carry charge

Group 4 Semiconductor if doped by addicting impurity

Group 5-8 DO NOT CONDUCT, no free electrons or ionsbto carry charge