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Atoms, periodically and chemical bonding., Chemical bonding - Coggle…
Atoms, periodically and chemical bonding.
Electrons exist in 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, each shell represents an energy level (first quantum number).
- Increasing number indicates shells they are further away from the nucleus and have higher energy state
The orbitals have different shapes in space, designated with different letters (eg s – sphere, p – dumb-bell)
(second quantum number) – also called sub-shells
The orbitals have different orientations in space eg s has only one orientation, p has three orientations (third
quantum number)
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Each degenerate (equal) orbital in a subshell (eg each p orbital) must be occupied by one electron before any
one of the orbitals becomes 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 is always filled before the P- orbitals (S has lower energy that P-orbitals)
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The valence shell holds those electrons located furthest from the nucleus. known a valence electrons.
Valence electrons interact with other atoms and are key to understanding an elements chemical reactivity.
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Representation of electrons as Lewis dot plots allow visualisation of electrons in the shell. (this does not distinguish between s and p orbitals
A valence shell may contain singly occupied orbitals (containing one unpaired electron) or fully occupied orbitals (containing a pair of electrons).
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If the electronegativity values of two atoms are similar they are most likely to undergo covalent bonding.
If there is a large difference in electronegativity values of the two atoms they are likely to undergo ionic bonding.
The distribution of electrons that are shared in a polar bond is skewed towards the most electronegative of the two atoms.
Chemical bonding
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The smallest number of electrons possible are redistributed (either accepted or donated) to achieve a full valence shell
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A molecular bonding orbital can be one of two types of bonds, A sigma orbital or a pi- orbital, which have contrasting shapes.
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Valence shell electron pair repulsion (VSEPR) theory allows us to predict the arrangement of valence
electrons pairs around a central atom
To use VSEPR
- count the valence electrons of the central atom,
- plus the electrons donated by the bonding atoms, and divide by 2.
- A molecule with a VESPR number of 4 forms a tetrahedral geometry