C3- Structure And Bonding

Question 1

What is the particle model?

Answer 1

It assumes that particles are made up of solid spheres with no force operating between them. This is useful to compare the properties of solids liquids and gases.

Question 2

What are the limitations of the particle model?

Answer 2

The particles that make up substances are atoms, molecules or ions and their interactions can distort the shapes. Atoms are mostly empty space, so real particles are not solid at all

Question 3

Ionic bonding

Answer 3

When elements react together to form compounds by losing or gaining electrons

Question 4

What ions so metals form?

Answer 4

Positive (as they lose electrons)

Question 5

What ions do non-metals form?

Answer 5

Negative (as they gain electrons)

Question 6

What are oppositely charged ions held together by?

Answer 6

Very strong forces of attraction

Question 7

The ionic bond between charged particles result in an arrangement of ions called a g____s_____ or g______L______

Answer 7

Giant structure or giant lattice

Question 8

What ions do Group 4 elements form?

Answer 8

Only tin and lead (bottom if the group) form ions either 4+ or 4-

Question 9

Why do ionic compounds have high melting points?

Answer 9

Because it takes a lot of energy to break the many strong ionic bonds, operating in all directions, that hold a giant ionic lattice together

Question 10

When can ionic compounds conduct electricity and why?

Answer 10

When molten or dissolved in water because the ions can become mobile and carry the charge through the liquid

Question 11

Covalent bonding

Answer 11

When atoms of non-metals share pairs of electrons (each pair is a covalent bond)

Question 12

Why do structure of simple molecules have low melting and boiling points?

Answer 12

Because they have weak intermolecular forces

Question 13

Why cant substances made up of simple molecules conduct electricity?

Answer 13

Because their simple molecules have no overall charge, so they can’t carry electrical charge, meaning the substance cannot conduct electricity

Question 14

Why are model drawings used?

Answer 14

To help us understand bonding, but they each have their limitations in representing reality

Question 15

Polymers

Answer 15

Made up of small reactive molecules that bond together to form large chains e.g poly(ethene)

Question 16

Whats a double covalent bond?

Answer 16

When the atoms share 4 electrons in one bond

Question 17

Whats triple covalent bond?

Answer 17

When the atoms share 6 electrons in one bond

Question 18

Do all covalently-bonded structures have giant structure?

Answer 18

No just some

Question 19

Giant covalent structure have ________ melting and boiling points

Answer 19

High

Question 20

Giant covalent structures are ________ in water

Answer 20

Insoluble

Question 21

Giant covalent structures are hard/ soft (?) and can/can’t (?)conduct electricity, apart from _________

Answer 21

Hard, can’t, graphite

Question 22

What can’t giant covalent bonds conduct electricity?

Answer 22

Because they have no free electrons as they are all involved in covalent bonding

Question 23

Why is Graphite soft and slippery?

Answer 23

Because they are no covalent bonds between its layers of covalently bonded carbon atoms. So the layes can slide over each other

Question 24

Why can graphite conduct electricity and thermal energy?

Answer 24

Because of its delocalised electrons that can move along its layers (as each carbon atom has 1 free electrons not used for bonding out of the 4 electrons,due to the layers being arranged in hexagons )

Question 25

The carbon atoms in Diamond have a ________ covalent structure, making it a very ________ substance

Answer 25

Rigid, hard

Question 26

What are fullerenes?

Answer 26

Carbon also exist as fullerenes and they can form large cage-like structures and tubes based on hexagonal rings of carbon atoms

Question 27

What are fullerenes started to be used in? (3)

Answer 27

• transport mechanism for drugs to specific site in the body
• catalysts
• reinforcement for composite materials

Question 28

What is Graphene?

Answer 28

A single layer of graphite and so its just 1 atom thick

Question 29

Name the properties of graphene

Answer 29

• excellent electrical conductivity
• excellent thermal conductivity
• low density
• strong for its mass
  These properties will help it develop in the electronics industry (specially due to its excellent electrical conductivity)

Question 30

Metallic bonding

Answer 30

Positive,y charged metal ions that are held closely together by delocalised electrons that are free to move throughout the giant lattice

Question 31

Why can metals be bent and shaped?

Answer 31

Because their layers of atoms (positively charged) in a giant metallic lattice can slide over each other

Question 32

Whats an alloy?

Answer 32

A mixture of 2 or more elements, at least one of which is a metal

Question 33

Why are alloys harder than pure metals?

Answer 33

Because the regular layers in pure metals are distorted by atoms of different sizes in an alloy

Question 34

Why are metals good conductors of thermal and electrical energy?

Answer 34

Because their delocalised electrons can readily flow through the giant metallic lattice and transfer the energy

Question 35

Whats the state of ionic compounds in room temperature?

Answer 35

All solids