bonding Flashcards
why is the bonding in magnesium higher than sodium
both are metallic bonded
magnesium has a greater charge(+2) than sodium ( +1)
thus Mg has twice as many e- in the sea of delocalised e-
Mg ions are smaller ,meaning a greater charge density
therefore the attraction between Mg2+ ions and delocalised e- is stronger
covalent bond
shared pair of electrons between two ions
the 3 macromolecular structures
silicon dioxide
silicon
carbon
ionic bonding
non metal and metal . gives electrons ,giant ionic lattice
coordinate bonds
shared pair of electrons however both shared pair comes from the same atom
2 bonding pairs no lone pair
planar
3 bonding pairs
no lone pairs
trigonal planar
120 bond angle
4 bonding pairs
no lone pairs
tetrahedral
109.5
5 bonding pairs
no lone pairs
trigonal bi-pyrmaidal
120 and 90
if not symettical ,what bonding is it and is it polar?
polar
permanent dipole dipole(second strongest*)
if symmetrical ,is it polar and what bonding is it?
non polar
van der waals
the formation of hydrogen bonding
h20 for example
large difference in electronegativity between oxygen and hydrogen
this polarises the O-H bond
there is a strong attraction between the lone pair of O and polar positive hydrogen atom of another molecule
the formation of permanent dipole dipole forces
HCL for example
difference in electronegativity between chlorine atom and hydrogen atom
polarises the H-CL bond.this creates a dipole
dipoles do not cancel out as the molecule is unsymmetrical
the attraction is between dipoles in neighbours
how to spot when a molecule has hydrogen bonding
H-F
H-O
H-N
how does induced dipole dipole(v.d.w) form
e.g CL2
random movement of electrons causes uneven distribution of electrons across a molecule
this forms a temporary dipole
this induces a dipole on another molecule
there is an attraction between dipoles in neighbouring molecules
