chapter 7 - covalent model Flashcards
what is a covalent bond
the electrostatic attraction between the positively charged nuclei of both atoms and shared pair of electrons
what is the simplest covalent molecule
H2
what is the octet rule
electrons shared so that the central atom has 8 electrons in the outer shell
what is a lone pair
a pair of electrons in the outer shell of an atom that is not involved in covalent bonding
how does a double covalent bond form
the sharing of 2 pairs of electrons
what is bond energy
the energy required to break a covalent bond
what is bond length
the distance between the nuclei of atoms making up a covalent bond (the length of a covalent bond)
order of decreasing bond energy (highest to lowest)
triple
double
single
are triple or double bonds longer and why
triple bonds are shorter due to the stronger attraction between the bonding electrons and the nuclei when there are more electrons in the bond
what is a coordination bond
a type of covalent bond where the electrons come from the same atom
aka dative covalent bond
electron domain geometry for 2 electron domains
linear 180
electron domain geometry for 3 domains
trigonal planar 120
electron domain geometry for 4 domains
tetrahedral 109.5
order of repulsion strength for pairs of electrons
lone pair - lone pair> lone pair - bonding pair > bonding pair - bonding pair.
What is electronegativity?
Electronegativity refers to the ability of an atom to draw electrons towards itself in a covalent bond
weakest to strongest intermolecular forces
london forces
dipole dipole forces
hydrogen bonding
are substances that can participate in hydrogen bonding soluble in water and if so why
yes because they can hydrogen bond to water
how do you calculate rf value
distance solute moves/ distance solvent front moves
properties of diamond
arranged in tetrahedral array
very high MP and BP and hard because covalent bonds must be broken when diamond is melted/boiled; requires lots of energy as the bonds are very strong.
does NOT conduct electricity(electrons held tight in covalent bond)
not soluble
properties of graphite
arranged in trigonal planar array
good lubricant - london forces between layers
high MP and BP
DOES conduct electricity - extra electron from p orbital
properties of graphene
a single layer of graphite
good electrical and thermal conductor
high tensile strength
high MP
c60 fullerene properties
insoluble in water
does NOT conduct electricity
it is a molecular structure
