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GCSE WJEC triple science Y11 wales > CHEMISTRY - Bonding, Structure and Properties > Flashcards

CHEMISTRY - Bonding, Structure and Properties Flashcards

1
Q

what does malleable mean

A

can be shaped easily

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2
Q

what does ductile mean

A

can be pulled into a wire

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3
Q

what is a cation

A

particle with a positive charge, normally metals

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4
Q

what does lattice mean

A

a structure where particles are arranged in a regular pattern

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5
Q

what are delocalised electrons (aka free electrons)

A

electrons in a substance which don’t belong to a single bond

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6
Q

what is an anion

A

particle with a negative charge, usually non metals.

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7
Q

what is an allotrope

A

different structures of the same element

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8
Q

name 2 properties of ionic compounds and give an example

A

-conduct electricity only as a liquid or in a solution
-have medium to high melting points

NaCl - sodium chloride

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9
Q

what are 4 properties of metals and give an example

A

-conduct electricity as a solid only
-most have high melting points
-strong attraction between cation and free electrons
-ductile/malleable

gold

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10
Q

what are 2 properties of simple molecules (covalent) and give an example

A

-have very low melting points
-dont conduct electricity

oxygen

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11
Q

what are 2 examples of giant covalent substance and 2 properties for both examples

A

diamond
-very high melting point
-doesnt conduct electricity

graphite
-very high melting point
-conducts electricity as a solid only

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12
Q

why are metals good conductors of electricity

A

because their electrons are free to move (delocalised/free electrons) which carry a current

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13
Q

which two things help to bind a metallic bond as a single unit

and why

A

cations - positive charge
delocalised/free electrons - negative charge

in a metallic bond the positively charged cations and the negatively charged free electrons are attracted to each other and bind the metallic bond as a single unit

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14
Q

what creates a stronger metallic bond, and how many stronger metallic bonds be different to weaker metallic bonds

A

more free electrons in the lattice allows the metals to use it to make a stronger bond

stronger metallic bond’s properties and weaker metallic bond’s properties can be different

eg.
strong metallic bond = aluminium has a melting point of 1205 degrees and is a better conductor

but weaker metallic bond = sodium has a melting point of 98 degrees and is a worse conductor

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15
Q

describe how a diagram of a metalic bond would look like

A

cations would be arranged in neat rows ontop of each other
and there are free electrons around it all

one free electron per cation

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16
Q

what type of force holds cations together inside the lattice

A

an electrostatic attraction

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17
Q

what are ions

A

positively or negatively charged particles formed when atoms lose or gain electrons

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18
Q

how does a metal atom form into a cation (positvely charged )

A

metal atoms lose the electron or electrons in their outer shell and become positively charged ions

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19
Q

how does a non-metal atom form into an anion (negatively charged)

A

non metal atoms gain an electron or electrons from another atom to become negatively charged ions

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20
Q

how to find out the number of charged on an ion formed by a metal

A

look at the group number of the metal

eg. Na is in group 1, so its Na+
Mg is in group 2 so its Mg ²+

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21
Q

how to find out the number of charges on an ion formed by a non metal

A

8 minus the group number

eg. oxygen is in group 6 so, 8-6 = 2, so O²+

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22
Q

what happens when metals react with non metals

A

electrons are transferred from the metal atoms to the non metal atoms, forming ions. The resulting compound is called an ionic compound

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23
Q

to get all the marks, what four things must you ensure that you do when you are drawing and ionic bonding diagrams

A

-show outer electrons of every atom at the start (1 mark)
-an arrow showing the electron transfer of the electrons (1mark)
-square brackets around every ion formed (1 mark)
-correct positive or negative charge next to every ion (1mark)

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24
Q

list the 4 main properties of ionic solids

A
  1. high melting point (cuz of the strong ionic bond)
  2. high boiling point (because of the strong ionic bond)
  3. soluble (meaning it dissolves)
  4. conductor of electricity when its dissolved. (ions are moving, carrying current)
25
Q

why do ionic compounds have such high melting points

A

strong electrostatic attraction (ionic bond) between the positive and negative ions

26
Q

why do ionic compounds conduct electricity when dissolved/ as a liquid but not when its a solid

A

because as a solid, the ions aren’t moving and they are fixed, so they cant carry any current, but when dissolved/ as a liquid, the ions are free to move and can carry the electric current.

27
Q

ionic bonds are forces of attraction between what?

A

between oppositely-charged ions
so positive and negative ions

28
Q

what is it called when a metal and non metal react together

A

ionic bonding

29
Q

what is it called when only non metals react together

A

simple covalent bonding

30
Q

how do non metals do simple covalent bonding if they both need to gain electron(s)

A

they share it

eg.

hydrogen atom has noly one electron and needs one more to complete it’s first shell (since first shell capacity is 2 electrons, and all other shells are 8 capacity) and so when two hydrogen atoms get close together their shells can overlap and they share their electrons.

you can write this as H-H , with 1 line in between it to show it is a single covalent bond.

31
Q

why do simple covalent bonds not conduct electricity

A

because the molecules are neutral - do not have any free electrons and carry no charge, so cant conduct electricity

32
Q

why do simple covalent bonds have low melting and boiling points

A

due to weak intermolecular attractions. the covalent bond within the molecules are strong, but the forces between the molecules (intermolecular forces) are weak and little heat energy can overcome the force, leading to low boiling and melting points.

33
Q

what are GIANT covalent bonds and give two main examples in GCSE chemistry

A

some covalent molecules are not simple compounds being formed from a few atoms,

they can be giant lattice structures with billions of atoms connected together - aka giant covalent bonds.

Diamond and Graphite (remember these two things, impotant)

34
Q

what is an allotrope

A

different forms of the same element in the same physical state

35
Q

describe what diamond is in terms of covalent bonds thingy

A

made up of a lattice of carbon atoms
each carbo atom can make 4 covalent bonds to 4 other carbon atoms
each out atom bonds to 3 more and so on
eventually millions of carbon atoms are bonded to form a giant lattice

36
Q

describe what graphite is in terms of covalent bonds thingy

A

is made up of flat sheets of carbon atoms
each carbon atom makes 3 covalent bonds to other carbon atoms
this gives rings of 6 atoms
the flat sheets that lie on top of each other are held by weak forces - sometimes called van de waal’s forces.

37
Q

what are the properties of diamond

A
  1. very hard- hardest known substance, each atom held to 4 others by strong covalent bonds - which is why it has a high melting point.
  2. doesn’t conduct electricity due to no ions or free electrons to carry charge.
38
Q

what are the properties of graphite

A
  1. soft and slippery due to sheets of atoms being able to slide over one another because of weak forces between them
  2. a good conductor of electricity. this is due to each atom only using 3 out of 4 electrons in bonding. the fourth electron of each atom becomes delocalized (free to move) throughout the lattice, enabling graphite to carry charge.
  3. high melting point due to strong covalent bonds holding atoms of carbon together in the rings.
39
Q

why does graphite conduct electricity?

A

3 out of the 4 electrons are used, and the 4th electron becomes free lectron, and carries electric curernt

40
Q

give two uses of diamond and graphite and explain them

A

diamond
-drill tips - hard due to strong covalent bonds between atoms
-cutting tools - hard due to strong covalent bonds between atoms

graphite
-used as a lubricant - weak intermolecular forces between layers so they can slide
-used in electrodes - has a free electron that can move and carry charge

*electrodes are like conductors if ya didnt know

41
Q

who discovered ‘bucky’ balls

A

sir harry kroto

42
Q

what are bucky balls

A

spherical balls made from 60 carbon atoms. each carbon is attached to 3 others by strong covalent bonds. There is one free electron so they can conduct electricity

43
Q

what are carbon nanotubes

A

another allotrope of carbon. they are molecular scale tubes of carbon atoms covalently bonded together with outstanding properties. each carbon is attached to 3 others by strong covalent bonds, with 1 free electron, so they can conduct electricity. they are flexible, strong and good conductors of electricity

44
Q

what is nanotechnology

A

technology using very very small particles and substances. so small that it isnt possible to see them with the naked eye. “Nano” means 1 billionth”

45
Q

name some properties of nano-particles of silver

A

-anti fungal
-anti bacterial
-anti virul

46
Q

name 4 uses for nano silver

A

-deodrant
-socks
-clothes
-plasters

47
Q

name two problems about nano silver

A

-long term effects aren’t known
-could be absorbed into your body and damage your health

48
Q

are the properties of nano silver and normal silver the same

A

no, a nano particle of silver has different properties

49
Q

name two other examples of nano particles other than silver and how they are used

A

nano particles of titanium oxide are added to sunscreen as it reflects UV radiation away

nano particles of gold can become red or orange or blue and can be stretchy. they can be used to connect conductors

50
Q

what are smart materials

A

when you heat a material such as iron, it becomes malleable but it is pretty useless

smart materials are materials that can change due to change in temperature, pH, light or other stuff, and the change in the material will be useful, and the change can also be reverted.

51
Q

name the 5 different types of smart materials

A

-thermochromic
-photochromic
-hydrogel
-shape memory polymer (polymer = plastic)
-shape memory alloy (alloy = metal)

both shape memory things are the same but theres 2 kinds, alloy and polymer

alloy is metal and polymer is plastic

52
Q

what are the properties of thermochromic paint and the use of it

A

property
-colour changes at different temperatures - reversible

use
-“flat” thermometers battery testers, coating on coffee mugs.

53
Q

what are the properties of photochromic paint and the use of it

A

property
-colour changes at different light intensity - reversible

use
-sunglasses, novelty items such as toys and cosmetics

54
Q

what are the properties of shape memory alloy and the use of it

A

property
-it can be deformed and if you heat it up, it will return to the original shape

use
-coffee pot thermostat, spectacle frames, stents for veins

55
Q

what are the properties of shape memory polymer and the use of it

A

property
-it can be deformed and if you heat it up, it will return to the original shape

use
-biodegradable surgical implants, self - repairing car bodies (easy dent removal)

56
Q

what are the properties of hydrogels and the uses of it

A

property
-can absorb large volumes of water and also expel it

use
-artificial muscles, robot actuators, removal of toxic chemicals, nappies

57
Q

what is the cause of the strength of a metallic bond?

A

the force of attraction between the positive charge metal ions and the negatively charged electrons.

58
Q

what is a dot and cross diagram

A

diagram to represent ionic bonding or covalent bonding

GCSE WJEC triple science Y11 wales (21 decks)

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