C2: Bonding Flashcards
What is an ion?
Electrically charges atom formed by a loss or gain of electrons
What is an anion
Negative ion (Gaines electrons)
What is a cation?
Positive ion (lost electrons)
What hold ionic compounds together?
Strong electrostatic forces between opposite charged ions
What is ionic bonding?
When non metals and metals react by transferring , they are held together by electrostatic forces between the opposite charged ions
What is covalent bonding?
Non metal atoms share electrons
What do metals form when they react, compared to non metals?
Mates lose electrons, non metals gain electrons
What is the structure of ionic compounds?
Giant ionic lattice (forms crystals)
Properties of a giant ionic lattice?
Regular arrangement of alternating negative and positive ions with strong electrostatic forces between opposite charges, acting in all directions
Properties of ionic compounds and why they have this
Solid at room temp : strong electrostatic forces
Conductor of electricity ONLY when molten: the negative ions are free to move and carry charge
Usually soluble in water: water has a positive and negative end, so ionic ions attract and dissolve
Dot and cross diagram for H2O, HCl, NH3, CH4, CO2
Properties of covalently bonded molecules and why
Don’t conduct electricity- no free electrons
Gases or liquids - weak bonds (intermolecular)
Low melting points
Strong intramoléculaires forces
What is an example of giant covalent structures?
Polymers (polyethene), graphite, diamond, silicon dioxide
Advantages and disadvantages of dot and cross diagrams?
A: useful for indicating the transfer of electrons
Shows which atom the bonding electrons came from
D: doesn’t show 3D arrangements
Does sos the relative size of atoms
Advantages and disadvantages of ball and stick model
A: shows 3D arrangements
Shows shape and size
D: doesn’t show moevement of electrons
Inaccurate gap sizes between atoms
Advantages and disadvantages of 2D diagrams of molecules
A: simple
Shows the atoms and how they are connected
D: can’t see the size and type of bond
Describe a metallic structure
Giant structure of positive ions arranged regularly, electrons of the outer shell ( valence electrons) and they form a sea of delocalised electrons
Properties of metallic ally bonded compounds and why
Conductors of electricity - delocalised electrons in the structure free to move through and carry charge
High m.p and strong: strong electrostatic forces Conductor
Malleable- layers which can slide
What is an allotrope?
Different arrangements of atoms of the same element
Allotropes of carbon?
Diamond, graphite
Describe the structure of diamond
Tetrahedron structure, strong intermolecular forces, each carbon atom formed 4 strong covalent bonds
Properties of diamond and why
Not conductor of electricity- no delocalised electrons Gases
High m.p- giant covalent structure with string intermolecular forces
Hard and dense- strong covalent bonds, each carbon atom forms 4 bonds, makes is useful in drill tips
Describe the structure of graphite
Layers of hexagons, weak intermolecular forces between layers, each carbon atom forms three covalent bonds, conductor
Properties of graphite and why
Conductor of electricity - one free electrons Gases per carbon atom, so it becomes delocalised in between the layers
High m.p- giant covalent structure, strong covalent bonds
Slippery- layers can slide and have weak intermolecular forces between them
Graphite can be used to make inert electrodes for electrolysis
What is graphene made from?
Carbon atoms, each one is covalent key bonded to 3 other (a single layer of graphite)
How big is graphene?
One carbon atom thick
Properties of graphene and why
Conductor- each carbon atom has one free electron which becomes delocalised
Strong and high m.p- intramolecular covalent bonds are strong
Transparent
Uses of graphene
Electronics like touchscreens, composite materials
What is fullerene made of?
A sphere of 60 carbon atoms
How big is a fullerene (buckminster ball)
1nm diameter
Properties of fullerenes
Slippery, low m.p
Uses of fullerenes
Drug delivery in the body, catalyst (surface area to volume ratio, lubricants
What is a nanotube made of?
Graphene rolled into a cylinder
How big is a nanotube?
A few nm wide and several mm long
Properties of nanotubes
Hugh tensile strength and resistant to breaking, conductors, high m.p
Uses of nano tubes
Electronic, tennis rackets
Uses of nanoparticles
Catalysts (high volume to surface area ratio)
Gives flexibility to surgical masks and medical clothing, deodorant, suncream, white pigment in paint
Advantages and disadvantages of nanoparticles
A: advanced technology without overuse
D: unknown risks, could breathe them in and pass into cells
