Chemistry 1.4 by Taylor keates https://padlet.com/taylorkeates/jaq8k99rm1jl Made with charisma en-us 2019-01-30 12:12:38 UTC 2026-03-01 17:10:34 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Soccerball.png VSEPR Theory 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795826 Valence Shell Electron Pair Repulsion

Groups of electrons around an atom(I.e a pair of electrons in the same orbital) will repel each other & take up positions as far apart as possible. The repulsion between electron pairs are minimised in this way.]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795826 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795827 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795827 VSEPR Ammonia example taylorkeates https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795828 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795828 Forces in bonded structures 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795829 All bonding results from electrical attractions and repulsion between protons and electrons with attractions greater than repulsion. 
ATTRACTION - 
  • e- pairs are attracted to the nuclei
  • opposite spin gives an attractive pair
REPULSION -
  • Repulsion between the nuclei 
  • Repulsion between pairs of electrons(pairs repel other pairs)
  • Repulsion between electrons in a pair
Covalent Bonds
The electrons in the pair between the atoms repel one another but this is overcome by their attractions to both nuclei.
If atoms get too close, the nuclei and their inner electrons will repel the other atom giving the bond a certain length.

Ionic Bonds
Cations and anions are arranged so that each cation is surrounded by several anions and vice versa. This maximises attraction and minimises repulsion. 
Attractive forces between positive and negative ions are over shorter distances therefore they are stronger.
Repulsive forces between like charges are over longer distances therefore they are weaker.
Repulsions from inner electrons and nuclei prevent the ions from getting too close together.
]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795829 Bond Polarity 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795830 Many bonds show an intermediate character between being purely ionic & being purely covalent.
Electron clouds -
Hydrogen chloride is an example of a polar molecule with a dipole, I.e it has a small charge of d+ and d- at each end.]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795830 Dipoles. taylorkeates https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795831 At any given time, one part of a molecule might be slightly more positive & the other side negative. These tiny changes influence neighbouring molecules, inducing(creating)the opposite charge in them & creating tiny forces of attraction between molecules. We form instantaneous dipoles or temporary dipoles which are often called van der Waals' forces.]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795831 Co-ordinate Bonds 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795832
  • Forms when both electrons forming the bond pair come from the same atom.
  • We use an arrow coming from the atom supplying the electrons to show these bonds.
    • ]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795832     Shapes of molecules 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795833 Bonding pair - a pair of shared electrons that make up a covalent bond
    Lone pair - a pair of electrons that don't make up a bond
    Strongest repulsion - lone pair-lone pair
               - lone pair-bonding pair
    Weakest repulsion - bonding pair-bonding pair

    Method - predicting shapes of molecules & ions
    1. Draw dot & cross
    2. List number of bonding pairs & lone pairs
    3. Suggest a VSEPR molecule shape 
    4. Sketch molecule showing bond pairs & lone pairs
    5. Apply the sequence for forces of repulsion to fully understand any distortion to the structure ]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795833     Metallic bonding 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795834
  • Consists of a lattice of positive ions held together by a sea of delocalised electrons given up by each atom.
    • ]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795834     Boiling points taylorkeates https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795835 Melting & especially boiling points increase with the strength intermolecular bonding. More electrons means more van der Waals forces and this requires more energy to break the bonds.]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795835 Forces between molecules 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795836 IntERmolecular bonding takes place between molecules & governs properties such as boiling point.
    IntRAmolecular bonding takes place within a molecule & governs the internal structure of the molecule.
    Forces between molecules(INTERMOLECULAR) are much weaker than covalent bond(INTRAMOLECULAR).]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795836     Ionic Bonds 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795837
  • Form between metals and non-metals
  • Form when one atom give one or more electrons to another atom, creating a cation and an anion. The two ions attract one another due to their new charges.

    • Example of ionic bonding
    ]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795837     Hydrogen Bonds 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795838 The hydrogen bond is a relatively strong intermolecular bond, having a hydrogen atom joined to a highly electronegative element having lone pairs(fluorine, oxygen, nitrogen). Hydrogen bonding is weak compared to bonding taking place within the atom, but is stronger than van der Waals. In water oxygen has 2 lone pairs & 2 hydrogen atoms, so forms a tetrahedral shape.]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795838 Covalent Bonds 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795839
  • Formed between non-metals (or to mak molecules)
  • Each atom gives an electron to form a bond pair, where each electron has opposed spin.

    • Example of covalent bonding
    ]]>     2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795839     Solubility taylorkeates https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795840 As well as hydrogen bonding with other water molecules, they can also dissolve other molecules such as the lower alcohols with which they can hydrogen bond. But non-polar organic molecules such as hydrocarbons cannot hydrogen bond with water are insoluble & prefer to interact with one another through van der Waals forces. ]]> 2019-01-30 12:12:48 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795840 Electronegativity 3185561 https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795841 The ability of an atom to attract electrons in a covalent bond. We can measure the pulling power of different atoms.
    The positive difference between the electronegativities of 2 atoms indicates bond polarity.
    ΔEN= 0 - pure covalent bonding
    ΔEN= 0 to 2.1 - polar covalent    (covalent with ionic)
    ΔEN= above 2.1 - pure ionic bonding    ]]>     2019-01-30 12:12:49 UTC https://padlet.com/taylorkeates/jaq8k99rm1jl/wish/325795841