Electronegativity and Polarisation:
Dot and cross diagrams don’t show length of bonds or shapes of molecules etc. Most bonds aren’t purely ionic or covalent due to polarisation à mix of covalent and ionic character
Only diatonic molecules or single elements are purely covalent
E.G Hydrogen... (draw)
Electronegativity - ability of an atom to attract a bonded pair of electrons in a covalent bond towards itself, fluorine is most electronegative.
Polar bonds between atoms with differing electronegativities, most electronegative pulls electrons towards itself.