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Topic 3 - Bonding - Coggle Diagram
Topic 3 - Bonding
Covalent Bonding
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It happens because the electrons are more stable when attracted to two nuclei than when attracted to one.
They shouldn't be regarded as shared electron pairs in a fixed position because the electrons are in a state of constant motion (charge clouds).
A dative covalent bond (coordinate bond) is a pair of electrons shared between two atoms , one of which provides both of the electrons to the bond
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Polar covalent - If one atom is more electronegative than the other, it attracts electrons more strongly so the electrons are closer to one atom causing slight positive and negative charges.
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Molecular Shapes
A sigma bind is a bond resulting from the direct overlap of two orbitals along the internuclear axis. It is only possible to form one sigma bond between two atoms since another would force too many electrons into one space
A pi bond is a bond resulting from the overlap of atomic orbitals above and below the internuclear axis. All double bonds consist of both a sigma and pi bond. Pi bonds can only be formed by the overlap of p-orbitals
VSEPR Theory: All sigma pairs and all lone pairs arrange themselves as far apart in the space as possible; pi pairs are excluded. Lone pairs repel more strongly than bonding pairs
- Two bonding pairs: linear 180, Three bonding pairs trigonal planar 120, Four electron pairs: Tetrahedral 109, Five bonding pairs: Trigonal Biprymidal 120 + 90, Six bonding pairs: Octahedral 90
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Metallic Bonding
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Are formed when atoms lose electrons and the resulting electron are attracted to all the resulting cations
It happens because the electrons are attracted to more than one nucleus (more stable). The electrons are delocalised - they are not attached to any particular atom but are free to move between atoms.
If both atoms are electropositive neither have a great ability to attract electrons so the electrons don't remain localised. Both atoms will have a positive charge.
Electronegativity
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It increases across a period as nuclear charge increase but shielding stays the same so electrons are more strongly attracted to the atom
It decreases across a group as the number of the number of shells increases so shielding increases and the electrons are less strongly attracted to the atom.
Ionic bonding
An ionic bond is an attraction between oppositely charged ions which are formed by the transfer of electron from one atom to another.
If the difference in electronegativity is large, the sharing of electrons is so uneven that the more electronegative atom will attract the electrons more strongly. The electron from one atom is transferred to the other one. One is negatively charge while the other is positively charged.
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