2.1 Periodicity

Question 1

How are elements in the periodic table arranged

Answer 1

Their proton number

Question 2

What does the group number indicate on the periodic table

Answer 2

The number of outer electrons of an element

Question 3

What elements are in each block of the periodic table

Answer 3

s-block = groups 1 and 2
p-block = groups 3 to 0
d-block = transition metals
f-block = radioactive elements

Question 4

What is periodicity

Answer 4

The study of trends within the periodic table often linked to elements’ electronic configuration

Question 5

What is the trend in atomic radius along a period

Answer 5

Atomic radius decreases

Question 6

Why does atomic radius decrease along a period

Answer 6

Due to an increased nuclear charge for the same number of electron shells
The outer electrons are pulled in closer to the nucleus because the charge produces a greater attraction

Question 7

What is the trend in atomic radius going down a group

Answer 7

Atomic radius increases

Question 8

Why does atomic radius increases going down a group

Answer 8

More electron shells, larger distance between outer electrons and nucleus reducing power of attraction
More electron shielding, nuclear attraction is reduced

Question 9

What is the trend in ionisation energy along a period

Answer 9

Ionisation energy increases

Question 10

Why does ionisation energy increase along a period

Answer 10

Because atomic radius decreases and nuclear charge increases
Outer electrons are held more strongly so more energy is required to remove the outer electron and ionise the atom

Question 11

Trend in ionisation energy going down a group

Answer 11

Ionisation energy decreases

Question 12

Why does ionisation energy decrease down a group

Answer 12

Nuclear attraction between nucleus and outer electrons reduces and shielding increases
Less energy is required to remove outer electron

Question 13

What does mtp of period 3 elements depend on

Answer 13

Structure of element
Bond strength

Question 14

What happens to mtp across period 3 between sodium and aluminium

Answer 14

All have metallic bonds, mtp increase due to greater positive charge
More electrons releases
More electrostatic forces so more energy is needed to break them

Question 15

Why does mtp increase dramatically for silicone in period 3

Answer 15

Very strong covalent structure
More energy required to break strong covalent bonds

Question 16

Why does mtp decrease in period 3 between phosphorus and chlorine

Answer 16

All simple covalent molecules with weak VDW
Less energy needed to overcome these weak imfs

Question 17

Why does argon have an even lower mtp than chlorine

Answer 17

Full outer shell of electrons
Very stable and VDW forces very weak
Less energy needed to overcome weak vdw forces