Chemical Bonding Flashcards
definition of ionic bonding
electrostatic attraction between positive and negative ions
definition of covalent bonding
pair of electrons are shared between two atoms
definition of metallic bonding
electrostatic attraction between delocalised electrons and metal ions
definition of electronegativity
the ability of an atom to attract the bond pair of electrons towards itself in a covalent bond
2 bonded pairs
linear
180
BeCl2
3 bonded pairs
trigonal planar
120
BF3
4 bonded pairs
tetrahedral
109.5
CH4
3+1 bonded pairs
pyrimidal
107
NH3
2+2 bonded pairs
V shaped
104.5
H2O
5 bonded pairs
trigonal bypyrimidal
120 + 90
PF5
6 bonded pairs
octahedral
90
SF6
dative covalent bonding
one atom provides both the electrons needed for a covalent bond
order of repulsion
lone pair-lone pair > lone pair - bond pair > bond pair - bond pair
intermolecular forces
vanderwaals/permanent dipole-dipole/hydrogen bonding
increase vander waals with..
number of electrons and contact points
what is needed for hydrogen bonding..
hydrogen atom and electronegative element + long pair of electrons
hydrogen bonding in water..
higher enthalpy change of vaporisation
surface tension
ice is less dense than water - long hydrogen bonds
definition of bond energy
amount of heat needed to break 1 mol of compound into gaseous atoms
definition of bong length
distance between the nuclei of two bonded atoms
definition of bond polarity
atoms having dipole moment or separation of charges
intermolecular forces influences..
bp/mp/temperature
bonding influences..
reactivity
electronegativity trend
increase across period, decrease down group
polar molecule has (2)
asymetrical distribution of electron charge
two atoms are partially charged
single covalent bond
s orbital
double covalent bond
pi bond
types of hybridisation
sp3/sp2/sp orbitals
