Structure and Bonding

Question 1

What happens to the bonds and intermolecular forces when a solid melts?

Answer 1

• The bonds remain the same
• Intermolecular forces are broken/weakened

Question 2

What is an ion?

Answer 2

An atom that has gained or lost electrons, it has a charge.

Question 3

Do metals form positive or negative ions?

Answer 3

Positive.

Question 4

Do non-metals form positive or negative ions?

Answer 4

Negative.

Question 5

What types of atoms form ionic bonds?

Answer 5

Metals and non-metals.

Question 6

What is the formula for a silver ion?

Answer 6

Ag⁺

Question 7

What is the formula for an ammonium ion?

Answer 7

NH₄⁺

Question 8

What is the formula for a zinc ion?

Answer 8

Zn²⁺

Question 9

What is the formula for a lead?

Answer 9

Pb²⁺

Question 10

What is the formula for an aluminium ion?

Answer 10

Al³⁺

Question 11

What is the formula for a nitrate ion?

Answer 11

NO₃⁻

Question 12

What is the formula for a sulfate ion?

Answer 12

SO₄²⁻

Question 13

What is the formula for a carbonate ion?

Answer 13

CO₃²⁻

Question 14

What is an ionic bond?

Answer 14

Electrostatic forces of attraction between oppositely charged ions.

Question 15

Which types of bonding have high melting/boiling points?

Answer 15

Metallic and ionic.

Question 16

In which sates can ionic compounds conduct electricity?

Answer 16

Liquid and aqueous.

Question 17

What types of atoms form covalent bonds?

Answer 17

Non-metals.

Question 18

What is a covalent bond?

Answer 18

A shared pair of electrons.

Question 19

What holds covalently bonded atoms together?

Answer 19

Electrostatic forces of atraction between the nuclei and the shared electrons.

Question 20

As size of a covalent molecule increases, what happens to the strength of the intermolecular forces?

Answer 20

They get stronger.

Question 21

What is an allotrope?

Answer 21

Different structural forms of a single element.

Question 22

Why is graphite a good electrical and thermal conductor?

Answer 22

Each carbon atom only forms 3 covalent bonds. So there is a delocalised electron which can move through the layers.

Question 23

How man covalent bonds can a carbon atom form?

Answer 23

4

Question 24

What is the structure of graphene?

Answer 24

• A single layer of graphite
• 2D
• Delocalised electrons

Question 25

What are the propertys of graphene?

Answer 25

- Strong - Light - Transparent - Electrical conducter

Question 26

What are the uses of fullerenes?

Answer 26

- Non-stick coatings for machinery - Cages to hold drug molecules - Molecular sieves (can trap large particles like viruses) - Chemical sponges (soak up toxic substances inside the body)

Question 27

How is a metallic bond formed?

Answer 27

- Electrons in the outer shells separate from the atom - These move freely around the metal ions

Question 28

What holds metallicly bonded atoms together?

Answer 28

Electrostatic forces between the metal ions and the delocalised electrons.

Question 29

Why are alloys stronger that pure metals?

Answer 29

- The different sized atoms distort the layers - Layers cant slide over each other - More force is needed to move the layers

Question 30

What are the propertys of metals?

Answer 30

- Conducters of heat and electricity - High melting points - Malleable and ductile

Question 31

What is the size of **coarse particles**?

Answer 31

1x10⁻⁵m

Question 32

What is the size of **fine particles**?

Answer 32

2.5x10⁻⁶m to 1x10⁻⁷m

Question 33

What is the size of **nanoparticles**?

Answer 33

1x10⁻⁷m to 1x10⁻⁹m

Question 34

What is the advantage of using nanoparticles over bulk material?

Answer 34

They have a larger surface area to volume ratio - so they react faster.