Bonding

metallic bonding

attraction between two delocalised electrons and positive ions arranged in a lattice

metallic bonding notes

greater charge on metal ion, greater attraction between ions and delocalised electrons therefore stronger bonds

smaller ions the closer to the positive nucleus the delocalised electrons are so greater attraction

graphite

layers planar hexagonal structures angle 120

lone pair repulsion

lone pairs are more repulsive than bonding pairs because they are closer to the central atom therefore closer to each other

shapes

Count the number of electrons on the outer shell of the

central atom (the one that is only 1)

Add to that number, the number of electrons that each

bonding atom brings

Add or remove any electrons for ions (charges)

Divide the number by 2 which will give you the electron pairs

Look at the molecule

electronegativity

the power of an atom to attract the pair of electrons in a covalent bond

electronegativity: atomic radius

radius of atom increases bonding pairs are further from the positive nucleus and less attracted to the positive nucleus therefore less electronegative

electronegativity protons

more protons means more electronegative due to greater attraction of electrons in the covalent bond

electronegativity shielding

full energy levels shield the electrons decreasing electronegativity

van der waals forces

weak and easily broken, caused by random electron movement, more electrons means stronger forces, longer molecule means stronger forces, more branches means less opportunity for chains to get closer to each other so fewer forces and less energy needed to break them

recognising van der waals

linear, symmetrical, non polar, momentary

PDPD

non symmetrical, polar, stronger than idid

hydrogen bonding

H + F, O, N, strongest intermolecular forces