Chapter 7 Periodicity

Question 1

What is first ionisation energy?

Answer 1

The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions

Question 2

List and describe the three main factors affecting ionisation energies

Answer 2

Atomic radius - The greater the distance between the nucleus and outer shell electrons, the less nuclear attraction

Nuclear charge - The more protons there are in the nucleus of an atom, the greater the attraction between the nucleus and the outer electrons

Electron shielding - Inner shell electrons repel outer shell electrons

Question 3

What are the trends in first ionisation energy down a group?

Answer 3

• Atomic radius increases
• More inner shells so shielding increases
• Nuclear attraction on outer electron decreases
• First ionisation energy decreases

Question 4

What are the trends in first ionisation energy across a period?

Answer 4

• Nuclar charge increases
• Same shell: similar shielding
• Nuclar attraction increases
• Atomic radius decreases
• First ionisation energy increases

Question 5

What is metallic bonding?

Answer 5

The strong electrostatic attraction between cations and delocalised electrons

Question 6

Why do metals conduct electricity?

Answer 6

Metals conduct in solid and liquid states because when a voltage is applied across a metal, the delocalised electrons can move through the structure, carrying charge

Question 7

Why do metals have high melting and boiling points?

Answer 7

High temperatures are necessary to provide the large amount of energy needed to overcome the strong electrostatic attraction between cations and electrons

Question 8

Describe diamonds structure and atom arrangement

Answer 8

Diamond is an example of a giant covalent structure

Has a tetrahedral arrangement of atoms and bond angles are all 109.5

Question 9

what are the 2 exceptions to giant covalent latticces being non-conductors of electricity?

Answer 9

Graphene and graphite

Question 10

Describe Graphene

Answer 10

• A single layer of graphite composed of hexagonally arranged carbon atoms linked by strong covalent bonds
• Thinnest and strongest material ever made
• Can conduct electricity

Question 11

Describe graphite

Answer 11

-Composed of parallel layers of hexagonally arranged carbon atoms

Question 12

Why do giant covalent structures have high melting and boiling points?

Answer 12

Covalent bonds are very strong so high temperatures are necessary to provide the large quantity of energy needed to break the strong bond