Unit 2

Question 1

How do you calculate relative atomic mass for isotopes?

Answer 1

Times the mass and percentage of isotopes together add the resultsand divide by 100.

Question 2

What is a positive ion called?

Answer 2

Cation

Question 3

What is a negative ion called?

Answer 3

Anion

Question 4

What is an ionic bond?

Answer 4

A strong electrostatic attraction between oppositely charged ions.

Question 5

Describe the structure of ionic compounds:

Answer 5

Giant lattice of ionic compounds as a regular arrangement of alternating positive and negative ions.

Question 6

What type of elements do ionic bonds occur between?

Answer 6

Metallic and non metallic

Question 7

2 properties of ionic compounds:

Answer 7

1. High melting and boiling points
2. Good electrical conductivity when aqueous or molten - poor when solid. (so charges/ions can flow freely)

Question 8

What is a covalent bond?

Answer 8

A covalent bond is formed when a pair of electrons is shared between two atoms leading to noble gas electroninc configurations

Question 9

2 properties of covalent bonded compounds:

Answer 9

1. Low melting and boilings points - weak intermolecular forces
2. Poor electrical conductivity

Question 10

2 giant covalent structures?

Answer 10

1. Diamond - cutting tools
2. Graphite - lubricant and electrode

Question 11

What is the structure of silicon (IV) oxide? SiO2

Answer 11

Each oxygen atom forms covalent bonds with 2 silicon atoms and each silicon atom in turn forms covalent bonds with 4 oxygen atoms. Tetrahedron

Question 12

What is metallic bonding?

Answer 12

The bonding from electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electrons

Question 13

2 Physical Properties of metallic bonded substances:

Answer 13

1. Good electrical conductivity
2. Malleability and ductility