Chapter 7 Periodicity

Question 1

Timeline of the atom 1803 - 1911

Answer 1

1803 - Dalton - Proposed that matter is made of tiny atoms.
1897 - Thompson - Realised that atoms are divisible and contain very tiny, negatively charged particles called electrons.
1911 - Rutherford - Realised atoms are made of a nucleus. The central nucleus is positvely charged and negative electrons revolve around this central nucleus

Question 2

Timeline of the atom 1915 - 1932

Answer 2

1915 - Bohr - Proposed electrons orbit the nucleus in a set size and energy.
1924 - Pauli - Proposed the concept of an electron spin
1932 - Chadwick - Discovered atoms contain neutral particles called neutrons.

Question 3

Ionisation energy

Answer 3

the amount of energy required to remove one electrons from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 4

How many ionisation energies can you have

Answer 4

As many ionisation energies as the amount of electrons

Question 5

Periodicity

Answer 5

A regular periodic variation of properties of element with atomic number and position in the periodic table.

Question 6

Factors affecting the ionisation energy

Answer 6

Atomic Radius - the force of attraction falls off sharply with increasing distance.
Nuclear charge - The number of protons. The greater the attraction between the nucleus and the outer electrons.
Electron shielding - Electrons are negatively charged so inner shell electrons will repel. Shielding effect.

Question 7

How can you tell Successive ionisation energies and shells

Answer 7

You can tell when there is a switch between shells. This is when there is a big jump on the graph.

Question 8

Trend in first ionisation energy down a group

Answer 8

First ionisation energy decrease down a group. Although the nuclear energy increase, its effect is outweighed by the increased radius and, to a less extent, the increased shielding.

Question 9

Trend in the first ionisation energy across a period

Answer 9

There is a general increase in first ionisation energy across the first three periods. At some points across the period there are drops in ionisation energy. These can be as a result of sub shells since they are filled up.

Question 10

Metallic Bonding

Answer 10

Bonding for metals
Delocalised electrons spread out around the structure.
The cations are fixed in position maintaining the structure.
Electrons are able to move.
The ions create a giant metallic lattice.

Question 11

Properties of metals

Answer 11

Strong metallic bonds - attracction between positive ions and delocalised electrons.
High electrical conductivity
High melting and boiling points.

Question 12

Electrical conductivity of metals

Answer 12

Conduct as solid and liquid.
When voltage is applied the delocalised electrons can move through the structure.

Question 13

Melting and Boiling points of metals

Answer 13

High melting and boiling points. This point depends on the strength of the metallic bonds holding together the atoms in the giant metallic lattice.

Question 14

Giant covalent structures

Answer 14

With non metals, many billion atoms are held together by a network of strong covalent bonds to form a giant covalent lattice.

Question 15

Melting and Boiling points of giant covalent

Answer 15

high melting and boiling points. This is because there are covalent bonds which are strong. High temperatures are necessary to provide the large quantity of energy needed to break the strong covalent bonds

Question 16

Solubility of giant covalent

Answer 16

are insoluble in most solvents. The covalent bonds are far too strong to be broken by interaction with solvents.

Question 17

Electrical conductivity of giant covalent

Answer 17

non- conductors.
except graphene and graphite - since they have three bonds and a delocalised electron.