3.1.1 Periodicity

Question 1

What are the rows in the periodic table called?

Answer 1

Periods

Question 2

What are the columns in the periodic table called?

Answer 2

Groups

Question 3

What blocks are there in the periodic table? (left to right)

Answer 3

S,P, D, F

Question 4

What does a block mean in the periodic table? E.g. s-block

Answer 4

What sub shell the outer electron(s) are in

Question 5

What is periodicity?

Answer 5

A repeating pattern across different periods

Question 6

How was the historical periodic table arranged?

Answer 6

• Ordered in increasing mass
• Groups according to similar characteristics
• Left gaps for unknown elements and could predict properties

Question 7

How is the current periodic table arranged?

Answer 7

• Ordered in increasing atomic number
• Groups = columns
• Periods = rows

Question 8

What is ionisation energy?

Answer 8

The minimum amount of energy required to remove one mole of electrons from one mole of gaseous atoms

Question 9

Is ionisation energy endothermic or exothermic?

Answer 9

Endothermic (+) requires energy

Question 10

What is shielding?

Answer 10

Shells of electrons reduces the pull of the nucleus/ the positively charged nucleus being able to attract negatively charged particles

Question 11

How does shielding affect ionisation energy? (increasing shielding causes …)

Answer 11

More electron shells -> more shielding effect -> weaker attraction between electrons in outer shell -> easier to remove electrons -> reduced ionisation energy

Question 12

How does atomic radius affect ionisation energy? (increasing atomic radius causes …)

Answer 12

Greater atomic size -> further away the electrons are from the nucleus -> reduced electrostatic attraction between nucleus and outer electrons -> easier to remove electrons -> reduced ionisation energy

Question 13

How does nuclear charge affect ionisation energy? (increasing nuclear charge causes …)

Answer 13

More protons in the nucleus -> greater nuclear charge -> greater electrostatic attraction between nucleus and electrons -> harder to remove electrons -> increased ionisation energy

Question 14

What is the trend in ionisation energies down a group? Why?

Answer 14

Decreases:

- More electron shells -> increased atomic radius and shielding

Question 15

What is the trend in ionisation energies across a period? Why?

Answer 15

Increases:

- More electrons and protons -> increased nuclear attraction

Question 16

What are the exceptions in the trend in ionisation energies across period 3?

Answer 16

1. Aluminium: electron in 3p shell, further away from nucleus and shielded by 3s so reduced ionisation energy
2. Sulfur: no change in shielding but electron repulsion in one of the 3p orbitals so same ionisation energy as previous element

Question 17

What is successive ionisation?

Answer 17

Removal of more than one electron from the same atom in a gaseous state

Question 18

What is the trend in successive ionisation?

Answer 18

Increasing energy required

Question 19

What drastically increases the successive ionisation energy?

Answer 19

Moving onto subshells/ shells that are closer to the nucleus

Question 20

What’s the structure and properties of Graphite?

Answer 20

• Each carbon bonded 3 times with 4th electron delocalised & layers that slide over each other
• High melting point, conducts electricity, low density, insoluble

Question 21

What’s the structure and properties of Diamond?

Answer 21

• Carbons bonded 4 times in tetrahedral shape (same to Silicon)
• High melting point, does not conduct electricity, insoluble

Question 22

What’s the structure and properties of Graphene?

Answer 22

• One layer of graphite made up of hexagonal carbon rings & Delocalised, free moving electrons which strengthen the covalent bonds
• Conducts electricity, lightweight, transparent, very strong

Question 23

What’s the structure of metallic bonding?

Answer 23

Metal cations donating outer electrons into sea of delocalised electrons in which they are electrostatically attracted to one another

Question 24

What makes metallic bonding stronger?

Answer 24

• Greater cation charge
• More electrons in sea of electrons
• Smaller ionic radius

Question 25

What are the properties of metallic bonding?

Answer 25

• Good thermal conductors
• Good electrical conductors
• High melting point
• Insoluble

Question 26

What determines the melting points for simple covalent molecules? Explain

Answer 26

How strong the induced dipole-dipole forces are by increased SA of the molecules;
More forces = higher MP