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Biochemistry lecture 2 - Coggle Diagram
Biochemistry lecture 2
Electrons exist within orbitals within an atom- an orbital is a region in space where there is a high probability of finding an electron
Orbitals are grouped into shells, representative of a energy level. increasing numbers indicate that the shells are further away from the central nucleus, they have a higher energy state.
orbitals have different shapes in space. , designed with different letters. (e.g. S- sphere, p- dumb bell) second quantum numbers also known as sub-shells.
the orbital have different orientations in space e.g. S only has one orientation, whilst P has (three orientations ( third quantum number)
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each degenerate (equal)orbital in a subshell ( each P orbital) must be occupied by one electron before any one of the orbitals become completely filled (Hund's rule)
An orbital can only contain two electrons and they must have opposing spins. (Pauli exclusion principle)
within a given shell, the S orbital must always be filled before the P orbital (S has lower energy than p) electron structure or oxygen (1s2 2s2 2p4)
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the valance shell holds electrons furthest away from the nucleus, know as valence electrons.
its the valence electrons that interact with other atoms, they are key to understanding a elements chemicals reactivity.
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A Lewis dot plot is used to visualise and represent electrons in the valence shell ( however it does not distinguish between S and P orbitals )
valence electron shells may contain singly occupied orbitals, or fully occupied orbitals.
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if the electronegativity values of two atoms are similar they are more likely to undergo covalent bonding. if there is a large difference in electronegativity values they are more likely to undergo ionic bonding.
the distribution of the electrons in polar bonds, favours the atom that is more electronegative.
ionic bonding is the strong interaction between two opposing charged ions. an ionic bond is formed when electrons are transferred from one atom to another.
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the atom with the smallest number of electrons redistributed (either accepted or donated) to achieve a full outer shell.
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A molecular bonding orbital can be one of two types: stigma orbital or pi orbital , which have contrasting shape.
Sharing one pair of electrons forms a covalent bond, whilst sharing two pairs of electrons forms a double covalent bond.
valence electron pair repulsion. (VSEPR) theory allows us to predict the arrangements of valence electrons pairs around the central atom.
to use VSEPR we count the valence electrons of the central atom, plus the electron donated by the bonding atom, and divide by 2. a molecule with a VESPR number of 4 forms a tetrahedral geometry.
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