Bonding, Structure and Properties of Matter Flashcards
What are the three forms of chemical bonding?
- Ionic
- Covalent
- Metallic
Which elements form an ionic bond?
Metals and non-metals
Describe ionic bonding.
An element will lose or gain electrons to have a full outer shell- the element is now charged and thus ionised. An ionic crystal lattice is formed between the elements; held by electrostatic attraction between oppositely charged ions.
What can ionic bonding form?
Giant ionic structures
Why do giant ionic structures form?
The strong electrostatic attraction produced from oppositely charged ions acts in all directions clumping ions together. Examples, Sodium chloride.
Which elements form a covalent bond?
Non-metals
Describe covalent bonding.
Electrons will be shared between elements to have full outer shells. This can be both large (e.g. Polymers) or (e.g. Monomers) small.
Name some giant covalent structures.
Diamond (carbon) and silicon dioxide
Which elements form a metallic bond?
Metals
Describe metallic bonding.
Electrons in a metals outer shell become delocalised and move through the whole structure. This gives rise to a strong bond. Atoms are arranged in a regular fashion.
What is the standard model for the states of matter?
That there are:
- Solids
- Liquids
- Gases
What are the limitations of the standard model for the states of matter?
The model assumes no forces are involved, all particles are represented as spheres and that they are solid/
What dictates the energy required to change the state of a substance?
The structure and the strength of the forces between the ions/ atoms. The stronger the forces the higher the energy needed to change state.
What are (and list) the state symbols?
The symbols given to define the state of a substance in a reaction;
Solid (s), Gas (g), Liquid (l) and an Aqueous solution (aq)
List the properties of ionic compounds:
- Strong electrostatic forces in a giant ionic lattice
- Strong intermolecular bonds (oppositely charged ions)
- High melting/ boiling point
- Conductive in an aqueous or liquid state as ions become able to freely move
List the properties of small compounds:
- Low melting/ boiling point
- Usually a liquid or gas at room temperature
- Weak intermolecular forces (stronger with size)
- Are not conductive
List the properties of polymers:
- Very long molecules
- Strong covalent (molecular) bonds
- Strong intermolecular bonds
- Solid at room temperature
- High melting/ boiling point
List the properties of giant covalent structures:
- All atoms in the substance are bonded together and so must be overcome to change state
- High melting/ boiling point
- Examples; Diamond, Graphite, SIlica
List the properties of metals:
- Giant structures with strong molecular bonds
- High melting/ boiling point
- Regular structure to atoms
- Layers slide past; pliable, can be bent or shaped
- Conductive
Why do we form alloys?
The mixture forms irregularities in the alloys structure. Thus, layers cannot slide past each other as easily and the material is harder.
What are the three/ four main possible pure forms of carbon?
Diamond, Graphite, Graphene, Fullerens
Describe diamond:
Each carbon atom bonds to four others in a giant covalent structure. Very hard but not conductive.
Describe graphite/ graphene:
Each carbon bonds to three others in layers. The structure is hexagonal with no links between layers. One electron from each atom is delocalised and it is thus conductive.
Graphene is a single graphite layer.
Describe fullerenes:
Carbon atoms bond in rings of several atoms in spheres or cylindrical tubes. The first discovered was the sphere Buckminsterfullerene. They are useful because; they are conductive (delocalised electrons), high length to diameter ratios. Can be used in nanotechnology, electronics and in new materials.
What are the scales of matter?
Coarse particles (PM₁₀) or dust, Fine particles (PM₂.₅) 100- 2500 nm, Nanoparticles 1-100 nm.
How do surface area and volume increase?
Both interact linearly in opposition to one another/ inverse.
Why are nanoparticles useful?
High surface area to volume ratio induces interesting properties.
How can nanoparticles be used?
Medicine, Electronics, Medicine, Cosmetics, Sun-cream, Deodorants, Catalysts.
What are possible harmful effects of nanoparticles?
Potentially toxic, could enter the brain through the blood. Additional research needs to be done before wider spread use.
