F332 - Elements of the sea

Notes based on the specification sheet.

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Electronic structure

Electrons have fixed energies. Electrons move around the nucleus in shells (or energy levels) - the further away a shell is from the nucleus the higher its energy.

There are sub-shells that have slightly differing energies.

Each sub-shell consists of a different number of orbitals (the bit of space where an electron moves).

Each orbital can hold up to 2 electrons, if there are 2 then they spin in opposite directions (spin-pairing). 

Electrons fill shells singularly before pairing up.

Cu and Cr will donate one of their 4s electrons to the 3d sub-shell as they are happier to have a full or half full 3d block as they are more stable.

Electronic structure can be used to determine the properties of an element. Eg s block elements losing their electrons in their outer shell to become a positive ion.

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Redox

Elements have an oxidation of 0.

The oxidation of a simple ion is the same as it's charge.

Transition metals have variable oxidation states.

The overall oxidation state of a compound is the same as it's overall charge.

The sum of the oxidation state of a neutral compound is 0.

Oxidation of oxygen is -2.

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Reaction mechanisms

Hydrolysis - Reactions involving the addition of water. (splitting by water).

Nucleophile - A reagent that forms a bond with it's reaction partner by donating a both bonding electrons. (has a lone pair to donate). It is attracted to areas dense in electrons.

Substation - A reaction where an atom or group of atoms is replaced by another atom or group of atoms.

Halogenalkanes can undergo nucleophilic substitution. 

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Reaction mechanisms

Electrophilic addition

Electrophile - Is a positive ion or molecule with a partial positive charge.

That will be attracted to a negatively charged region.

And will react by accepting a lone pair of electrons to form a covalent bond.

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