Bonding and Properties of Matter

Question 1

what ion do group 1 form? (metal)

Answer 1

+1 ion

Question 2

what ion do group 2 form? (metal)

Answer 2

+2 ion

Question 3

what ion do group 6 form? (nonmetal)

Answer 3

-2 ion

Question 4

what ion do group 7 form? (nonmetal)

Answer 4

-1 ion

Question 5

what is covalent bonding

Answer 5

the sharing of electrons between 2 non metals

Question 6

what is ionic bonding

Answer 6

the transfer of electrons from a metal to non metal

Question 7

describe the properties of pure metals & why they are like this

Answer 7

• conduct electricity & heat easily (delocalised electrons can carry the electrical current/thermal energy)
• soft (have layers meaning they can slide across each other)

Question 8

describe the properties of alloy metals & why they are like this

Answer 8

• hard (have distorted layers so cannot slide across each other)

Question 9

what is the structure of ionic compounds

Answer 9

• giant ionic lattice

Question 10

describe the properties of ionic compounds & why they are like this

Answer 10

• high melting and boiling point (have many bonds so takes lots of energy to break them)
• only conducts when molten or dissolved (ions must be free to move)

Question 11

describe the properties of simple covalent compounds & why they are like this

Answer 11

• low melting/boiling points (molecules joined by strong covalent bonds but held together by weak forces thatre easily broken)
• dont conduct electricity (2 non metals so no delocalised electrons)

Question 12

give examples of simple covalent compounds

Answer 12

• H2O
• CO2
• HCl

Question 13

give examples of ionic compounds

Answer 13

• MgO
• NaCl
• KBr

Question 14

give examples of alloy metals

Answer 14

• steel
• brass
• bronze
• gold (in jewellery)

Question 15

give examples of pure metals

Answer 15

• gold
• silver
• sodium

Question 16

give examples of giant covalent compounds

Answer 16

• fullerenes ie buckminsterfullerene
• graphite
• diamond
• silica

Question 17

describe the properties of giant covalent compounds & why they are like this

Answer 17

• high metling/boiling points
• do not conduct electricity
• do not dissolve

Question 18

what is the structure of diamond

Answer 18

• giant covalent structure
• made of pure carbon
• each carbon bonded to 4 other atoms

Question 19

describe why the properties of diamond make it useful

Answer 19

• very hard bc of the many bonds

- we can use it in drills

Question 20

describe why the properties of graphite make it useful

Answer 20

• layers of graphene slide over each other weak forces btwn the layers so is very soft
• conducts electricity (delocalised electrons move through the graphite, carrying charge)
• v.high melting/boiling point (lots of v. strong covalent bonds so lots of energy needed to break them)
• we use it for lubricants and pencils

Question 21

what is the structure of graphite

Answer 21

• made of layers of graphene
• made of pure carbon
• each carbon makes 3 bonds with other atoms

Question 22

compare the properties of buckminsterfullerenes and carbon nanotubes

Answer 22

• both: pure carbon, make 3 carbon bonds, hard, used for drug delivery
• buckminsterfullerene used for reinforcements in buildings

Question 23

what are polymers

Answer 23

• Polymers are very large molecules made when many smaller molecules join together, end-to-end
• Alkenes can be used to make polymers.
• smaller molecules are called monomers
• lots of monomer molecules → a polymer molecule

Question 24

give uses of certain polymers

Answer 24

• polyethen used for plastic bags and bottles
• polypropene used for crates and ropes
• polychloroethene used for water pipes and insulation on electricity cables

Question 25

give examples of alkenes forming polymers

Answer 25

Alkenes can act as monomers because they have a double bond: Ethene can polymerise to form poly(ethene),AKA polythene. Propene can form poly(propene), AKA polypropylene.

Question 26

compare properties of polymer chains with cross links and without cross links

Answer 26

- polymers with cross links (cannot slide across each other: fixed in place, burn upon heating) - polymers without cross links (can slide across each other so melt upon heating))

Question 27

what is nanotechnology

Answer 27

- rearranging/ manipulating atoms to make other useful structures - about 100 nanometres across.

Question 28

describe the properties of nanotechnology & why they are like this

Answer 28

- high surface area to volume ration (as you get smaller, you increase surface area) - strong forces btwn surfaces/ reactive(Atoms on the surface of a material more reactive than in the centre, so a larger SA means the material is more reactive.)

Question 29

what are the uses of nano technology

Answer 29

- sports equipment: added to materials to make them stronger whilst being lighter. used in tennis rackets - clothing: silver nanoparticles added to socks, stopping them from absorbing foot odour as the nanoparticles have antibacterial properties - healthcare: used in sunscreens,offering protection and can be rubbed in so there are no white marks.

Question 30

what are the concerns about nanopartilces

Answer 30

Harmful effects - may be able to enter the brain from the bloodstream and cause harm(toxic). - Some people think more tests should take place before nanoparticles of a material are used on a wider scale.