Topic 1.3- Key concepts/ types of a substance

Question 1

Why can elements be classified as Ionic, Simple/giant covalent, or metallic.

Answer 1

-Different atoms cuase different bonds:
- Ionic, Covalent or metallic bonds.

Question 2

What is an ionic structure?

Answer 2

• Gas (non-metal) and a metal
• Held together by strong electrostatic forces between charged ions
• E.g magnesium oxide

Question 3

What is a simple molecular structure?

Answer 3

• Strong covalent bonds between thee atoms of the molecules
• Weak intermolecular forces between the molecules (e.g water)

Question 4

What is a giant covalent structure?

Answer 4

• Covalent bonds form one structure
• Graphite, diamond

Question 5

What is a metallic structure?

Answer 5

• Lattice of positive metal ions
• and free electrons
• Strong electrostatic forces of attraction

Question 6

What and why is Ionic melting point?

Answer 6

-High
-Strong electrostatic forces between the positive metal and negative gas

Question 7

What and why is simple molecular melting point?

Answer 7

-Low
-Covelant
-Weak intermolecular forces between molecules

Question 8

What and why is giant covalent melting point?

Answer 8

-High
-It is NOT A molecule and therefore has no weak intermolecular forces between molecules
-Strong electrostatic forces

Question 9

What and why is Metallic melting point?

Answer 9

-High
-Strong electrostatic forces between delocalised electrons and positive ions.

Question 10

What and why is Ionic bonds physical state?

Answer 10

-solid
-high melting point

Question 11

What and why is simple molecular bonds physical state?

Answer 11

-gas
-low melting point

Question 12

What and why is giant covalent bonds physical state?

Answer 12

-solid
-high melting point

Question 13

What and why is metallic bonds physical state?

Answer 13

-solid high melting point

Question 14

What and why is Ionic solubility in water?

Answer 14

• Many are soluble
• Water molecules ( electrons are generally closer to oxygen as oxygen has more protons)
• In water Oxygen is more negative and hydrogens are more positive
• Positive metal will move to oxygen
• Negative gas will move to hydrogen

Question 15

What and why is simple molecular solubility in water?

Answer 15

• Few are soluble
  -Water is polar and simple molecular structures are normally non-polar

Question 16

What and why is/isn’t giant covelant solubility in water?

Answer 16

-Insoluble
-Strong covalent bonds

Question 17

What and why is metallic solubility in water?

Answer 17

-Insoluble
-Non polar and water is polar

Question 18

What and why does/ doesn’t Ionic conduct electricity?

Answer 18

-Only in molten form/ in solution
- Ions can move freely

Question 19

What and why does/ doesn’t simple molecular conduct electricity?

Answer 19

• Most do not
• they are neutral

Question 20

What and why does/ doesn’t giant covalent conduct electricity?

Answer 20

• Most do not conduct
• Most have no free electrons

Question 21

What and why does/ doesn’t metallic conduct electricity?

Answer 21

• Can conduct
• Free delocalised electrons

Question 22

What are two main examples of giant covalent structures made of carbon?

Answer 22

• Diamond
• Graphite

Question 23

What is the structure of graphite?

Answer 23

• One atom thick
• Light
• Strong
• Conducts electricity
• high melting and boiling point

Question 24

Why can graphite conduct electricity?

Answer 24

• Graphite is made of three carbon atoms bonded to one carbon atom
• Carbon has 4 electrons on outer shell
• One free electron
• Hexagonal shape
• High melting point

Question 25

Why does graphite have a high boiling point? | Despite weak intermolecular forces between layers

Answer 25

- Strong covalent bonds

Question 26

Properties of diamond?

Answer 26

- Very strong - High melting/ boiling point - Does not conduct electricity - rigid lattice structure

Question 27

Why can't diamonds conduct electricity?

Answer 27

- Carbon has four bonds each, no free electrons

Question 28

Why do diamonds have a high melting/boiling point?

Answer 28

- No weak intermolecular forces - All strong covalent bonds between atoms

Question 29

Why is diamond used in cutting?

Answer 29

- Strong - Hard - strong covalent bonds

Question 30

Why is graphite used in lubrication?

Answer 30

- Hexagonal sheets can slide past each-other due to weak intermolecular forces. - Soft, slippery - High melting point due to strong covalent bonds

Question 31

Why is graphite used in electrodes?

Answer 31

- Free electron

Question 32

What is graphene and what are its properties? | thickness, electrical, boiling points

Answer 32

- One layer of graphite - Conducts electricity (free electrons) - High melting/boiling point (no layers, no weak intermolecular forces)

Question 33

What are fullerenes?

Answer 33

-Hollow carbon structures - Made of hexagonal shapes ( could have parts of 5, or 7 connected, pentagonal or heptagonal)

Question 34

What was the first fullerene

Answer 34

- Buckminsterfullerene - 60 carbon atoms - Ball shape

Question 35

What are the uses of fullerenes like Buckminsterfullerene?

Answer 35

- Deliver drugs - Lubricants - Catalysts

Question 36

Uses of carbon Nanotubes ? | (rolled graphene sheet)

Answer 36

- Very long, small diameter - Extremely elastic - Reinforce materials ( tennis rackets)

Question 37

Describe poly(ethene)

Answer 37

- C2H4 - chain of carbon that consists of large molecules - Hydrocarbon

Question 38

Metals properties?

Answer 38

- Conduct electricity - free delocalised electrons - Malleable, uniform layers can slide over each-other.

Question 39

Describe most metals?

Answer 39

- High melting and boiling point - Shiny - Conduct electricity well

Question 40

Describe most non- metals

Answer 40

- Low melting and boiling point - poor conductors of electricity

Question 41

Limitations of the dot and cross diagram?

Answer 41

- Not 3-D - looks like electrons are different

Question 42

Limitations of the ball and stick diagram?

Answer 42

- Atoms are far apart - Doesn't include electrons are protons

Question 43

Ideas needed to see in models?

Answer 43

- Electrons the same - Protons - 3-D - Bonded and close together - Respective sizes of atoms - Number of atoms included

Question 44

What are nano particles?

Answer 44

-small particle (abt 1nm-100nm) -Larger than an atom or a molecule

Question 45

What are nano particles used for?

Answer 45

-sunscrean (very small + absorbant) -eyeglasses -crack resistant paint -drug delivery -More durable tennis rackets

Question 46

What are the dangers of nano particles?

Answer 46

- Untested - Very small can be absorbed by bloodstream