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28 Cards in this Set
- Front
- Back
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Describe a ionic compound? |
Ion dipole of water molecule attractive forces realease energy ion dipole forces Na+ to O and Cl- to H. |
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Descibe the enthalpy in an ionic compoud? |
If enthalpy of ion hydratiom exceeds enthalphy of lattice dissocation then solubility is likely. |
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Describe the melting points of ionic compound? |
High melting points hard and yet brittle. |
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What are water molecules surrounded by? |
Aq ions. |
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Describe the structure of Metallic bonding? |
Is malleable because layer of metal ions can slide over each other and re-form strong metallic bonding. Delocalised electrons are mobile and able to transfer electrical charge. |
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Describe the molecular(gases) formuli? |
H2 |
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Describe molecular crystal(liquids/solids) formula? |
l2 ice |
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Describe the giant covalent monomolecule formuli? |
Diamond graphite SiO2 |
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Describe the simple covalent molecular? |
In solid, idione, the molecule are held together by intermolecular forces (the magnitude of van der waals forces increases with molecular size (mr)) |
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What is dipostion? |
gas to solid |
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What is sublimintation? |
solid to gas. |
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What is co-cordinate (dative covalent) bonding? |
Shared pair of electrons with both electrons originating from one atom and donated to other atom. |
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Describe how to decribe the increase/decrease in boiling point? |
As the boiling point increases/decreases because it has a larger/smaller molceluar size therefore, the stronger/weaker forces so more/less energy is needed to sperate the intermolecular forces. |
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Describe the diamond structure? |
Diamond exists as a giant covalent macromolecule. Each carbon atom is covalently bonded to 4 other carbon atoms. There are many strong covalent bonds arranged in a tetrahedrial arrangment. Condiserable energy is needed to break the many strong covalent bonds as part of the melting process. |
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Describe the structure of graphite? |
Graphite exists as a giant covalent maromolcule. Each carbon atom is covalently bonded to 3 other carbon atoms. Graphite exists as layers of hexagonal carbon rings (layers of graphene) serprated by weak intermolceluar forces. Considerable energy is needed break the many strong covalent bonds within the graphene layers, hence graphite as a high melting point. |
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Describe why graphite can be used as a lubricant? |
Had weak IMF allowing layers to slide over each other. |
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Describe the structure of Graphene? |
Single layer of hexagonally packed carbon atoms, each layer is 1 atom thick, considered a 2 dimensional lattice. Each carbon atoms forms 3 covalent bonds therefore, graphene has many strong covalent bonds, making graphene have higj strength amd melting point. Each carbon atom has a single unbound electrons that is delocalised and mobile. Exclllent conductor of electrically and themal energy. High strength and melting point. |
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Describe electronegativity? |
Power of an atom to attract to attract the pair of electrons in a covalent bond. |
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What is electronegativity for non polar? |
0-0.3 |
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Describe is electronegativity polar? |
0.3-1.8 |
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Describe the electronegativity for an ionic bond? |
>1.8 |
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Describe polarisation? |
Polarisation of ionic bonding signifies the unequal distribution of electrom density around the anion caused by properties of the carbon anion. |
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Describe why Al3+ ion has a greater polarising ability than Mg2+ ion? |
It has a higher charge density (higher nuclear charge and lower ionic radius) |
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Describe Dipole-Dipole intermolecular forces? |
They are permanent dipole-dipole forces(dotted lines). They have a high electronegativity difference so they have a high covalent bond which causes polarisation which means high magnitude of dipole(charge seperation) so high strenght of dipole-dipole IMF |
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Explain Dipole-Dipole bonding of H2O? |
Oxygen is more elctronegative than H Induces a covalent bond (H+,O-) There is hydrogen bonding between lone pair O and H |
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What is the formula for Steric number? |
Number of bonding pairs+number of lone pairs(E) |
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What is the valence shell electron pair repulsion (VSERR) theory? |
When the outershell(valence) electrons pairs arrange themselves as far apart as possible to minimise repulsion Lone pair=lone pair repulsiom is more than Lone pair=bond pair repulsion is more than Bond pair=bond pair repulsion |
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How would you describe a steric? |
How many bonding pairs How many lone pairs Electron pairs repel each other. Lone elctron pair has greater repulsion/if no lone pairs there is an equal repulsion. Molecules takes ...... shape to minimise repulsion Bond angle is hence........ |
