4.2.1🐚

Question 1

What is a compound?

Answer 1

Substances in which 2 or more elements are chemically combined.

Question 2

What are the 3 types of chemical bonds:

Answer 2

Ionic, covalent and metallic

Question 3

When does an ionic bond occur?

Answer 3

Particles are oppositely charged ions. They occur in metals and non metals.

Question 4

When does a covalent bond occur?

Answer 4

Occur between 2 non metals. Particles are atoms which share a pair of electrons

Question 5

When does a metallic bond occur?

Answer 5

Occurs in metals and alloys. Particles are atoms which share delocalised electrons

Question 6

Describe how an ionic bond occurs (4 marks)

Answer 6

When a metal and non metal react. Electrons on the outer shell of a metal atom are transferred. Metal atoms loose electrons and become positively charged ions. Non metals gain electrons and become negatively charged ions. They are held together by electrostatic forces of attraction

Question 7

What are electro static forces of attraction:

Answer 7

The attraction between oppositely charged ions.

Question 8

What structure do the ions produced in groups 1 and 2, non metals in groups 6 and 7 have?

Answer 8

The electronic structure of a noble gas

Question 9

How are ionic compounds represented?

Answer 9

Dot and cross with brackets and charge outside.

Question 10

Describe the structure of an ionic compound:

Answer 10

A giant structure of ions, held together by strong electrostatic forces of attraction between oppositely charged ions. These forces act in all directions

Question 11

How are ionic compounds represented:

Answer 11

Ball and stick, 2 and 3 dimensional diagrams.

Question 12

What are limitations of using diagrams to represent ionic compounds?

Answer 12

Assumes ions are the same size and shape. You cant see forces of attraction.

Question 13

Give an example of an ionic compound:

Answer 13

Sodium chloride

Question 14

What is covalent bonding:

Answer 14

When atoms share one or more pairs of electrons.

Question 15

What are the types of covalent structures?

Answer 15

Small or simple molecules, polymers and giant covalent structures.

Question 16

What are examples of small molecules?

Answer 16

Ammonia, methane, oxygen, hydrogen…

Question 17

What are examples of giant covalent structures:

Answer 17

Diamond and silicon dioxide.

Question 18

How are covalent bonds represented:

Answer 18

Dot and cross, repeat units, ball and stick, 2 and 3 dimensional diagrams

Question 19

Describe a metallic bond;

Answer 19

Metals consists of giant structures of atoms arranged in a regular pattern. The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure. The sharing of delocalised electrons allows for strong metallic bonds.

Question 20

How does a metallic bond occur?

Answer 20

2 metals, outer shell electrons become delocalised, resulting in the metal atoms forming positive ions. There are then electrostatic forces of attraction holding the ions and delocalised electrons together.