1-review Flashcards
formal charge formula
(group #) – (# of bonds) – (# of non-bonded electrons)
what are exceptions to the octet rule (2)
- incomplete octets common for first-row elements`
- expanded octets: common for elements with d orbitals
definition of electronegativity
ability of an atom to attract shared electrons in a bond towards itself from the surrounding atoms
what are bond dipoles
polarization of the bond
de Broglie regarding movement of electrons
the electrons’ movement can be described by mathematical equations (waves’ equations)
schrödinger regarding movement of electrons
this movement is related to a series of energy levels (solutions to waves’ equations)
heisenberg and Born regarding movement of electrons
the exact position of an electron cannot be determined (probability region)
probability of finding electrons in nodes
probability of finding electrons on the top and bottom nodes of the p orbital is the same, in the middle is 0
vsepr theory of electrons
to determine three-dimensional distribution of electrons around atoms.
valence bond model
probability of finding the shared spin-paired electrons is confined to the regions between the atoms (localized bonds).
definition of hybrid orbitals:
result from mixing atomic orbitals s and p to give a sp type of orbital.
hybridization sp3
1 s orbital, 3 p orbitals, tetrahedral, SN = 4
hybridization sp2
1 s orbital, 2 p orbitals, trigonal planar, SN = 3
hybridization sp
1 s orbital, 1 p orbital, linear, SN = 2
in what type of orbitals do lone pairs reside
As for the lone pairs, the ones that contribute to the resonance and by that were delocalized into an adjacent bond will be in 2p orbitals and the one that didn’t will reside in a sp2 orbital. otherwise it’s just matches the main atom that it’s on
what is resonance
concept developed to explain the structures that can’t be explained by simple Lewis structures. electrons are delocalized (shared) between multiple atoms via p orbitals. resonance hybrids are the true structures
how many arrows with empty orbitals (resonance)
only show one arrow per resonance form
how many arrows with excess orbitals (resonance)
show two arrows per resonance form
list the three resonance contributors
- incomplete octet (it becomes the minor contributor right away)
- charge (which one has lowest charge, becomes major contributor)
- electronegativity (more EN atom, it will accommodate charge better)
list of 5 things to look for in major resonance form
- The most atoms with complete octets.
- fewest number of formal charges
- The most covalent bonds
- negative charges on most electronegative atoms and positive charges on least electronegative atoms
- charge separation: like charges have max separation and unlike charges have min separation
list of 4 things to look for in minor resonance form
- The most atoms with the least filled octets
- Resonance contributors in which there is a greater separation of charge
- A resonance structure with a lower number of total bonds
- Negative charge is located on the less electronegative atom
what are atomic orbitals
formed by an electron cloud around an atom, it is the region having the highest probability of finding an electron in an atom
what are molecular orbitals
formed by a combination of atomic orbitals, it is the region having the highest probability of finding an electron in a molecule. the number of molecular orbitals formed is equal to the sum of atomic orbitals combined.
what are the two possibilities of overlapping
- in-phase overlap: bonding (sigma, pi)
- out-out-phase overlap: anti bonding (sigma, pi)