Chemical Bonding Flashcards
covalent compounds
partial sharing leads to a covalent bond
ionic compounds
transfer of electrons from one element to another (metal to nonmetal)
metallic bonding
electrons are pooled: atoms are kept together through the interaction of the positively charged nuclei with a cloud of electrons that is shared between all atoms
atoms that differ in electronegativity
the electrons are attracted by the atom with higher electronegativity
resonance forms
the electrons are delocalized in a hybrid structure: identical bond lengths
how do we distinguish between plausible bonding schemes?
by choosing the structure with the smallest formal charge and the negative charge on the more electronegative atom
formal charge
number of valence electrons - number of lone pairs - number of bonding electrons/2
radicals
species with an odd number of electrons and are usually unstable and very reactive
which elements can form more than 4 bonds
if an atom belongs to the 3rd period or more
when will a bond form
if there is an energetic gain in the process
bond energy
the energy required to break one mole of identical bonds
vsepr
electrons in bonds and lone pairs will arrange in space to minimise charge- charge repulsions
linear geometry
180 degrees
2bp
trigonal planar geometry
120 degrees
3bp
tetrahedral geometry
109.5 degrees
4bp
bent
2bp + 2lp
trigonal pyramidal
3bp + 1lp
how can a bond be polarised
due to the electronegativity difference between the atoms.
hybridization
the combination of different atomic orbitals with similar energies to form isoenergetic orbitals identical in shape
why is h2O a bent molecule
due to hybridization
sigma bond
formed by the head-on overlap of atomic orbitals
strength pi and sigma bond
pi bonds are weaker than sigma bonds
discuss the rotation around a single or a double/triple bond
rotation about a single bond is free, around double or triple bonds is not
draw the molecular orbital diagram for when Zavg is less than 8
see notes
draw the molecular orbital diagram for when Zavg is greater or equal to 8
see notes
bond order
bond order = (electrons in bonding orbitals - electrons in antibonding orbitals)/ 2
bonding molecular orbital
the sum of the wave function: a region where it is more likely to find an electron
antibonding molecular orbital
subtraction of the wave function: does not favor the formation of a molecule
paramagnetism
unpaired electrons: attracted to the magnetic field
diamagnetism
paired electrons: repelled by a magnetic field
