Chapter 7 - Periodicity

Question 1

What is periodicity?

Answer 1

The repeating trend in properties of the elements across each period

Question 2

What is the first ionisation energy?

Answer 2

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

Question 3

What are the three factors affecting ionisation energy?

Answer 3

Atomic radius, nuclear charge and electron shielding

Question 4

Why do first ionisation energies decrease down a group?

Answer 4

Atomic radius increases, more inner shells so shielding increases and nuclear attraction on outer electron decreases

Question 5

Why do ionisation energies across a period increase?

Answer 5

Nuclear charge increases, same shell (similar shielding), nuclear attraction increases and atomic radius decreases

Question 6

Why is there a small decrease in ionisation energy between beryllium and boron?

Answer 6

The outer sub shell in boron has a higher energy than the 2s orbital of beryllium which makes the electron easier to remove

Question 7

Why is there a small decrease in ionisation energy between nitrogen and oxygen?

Answer 7

In oxygen the 2p electrons are paired up and repel each other which makes it easier to remove the electron from oxygen

Question 8

What is metallic bonding?

Answer 8

The strong electrostatic attraction between cations and delocalised electrons

Question 9

What comments can be made about boiling and melting points, solubility and electrical conductivity in metals?

Answer 9

High melting and boiling point, not soluble and can conduct electricity in solid and liquid states

Question 10

What comments can be made about boiling and melting points, solubility and electrical conductivity in giant covalent lattices?

Answer 10

High melting and boiling point, insoluble and non conductors except from graphene and graphite