chemistry - covalent bonding

define covalent bond (2)

• strong electrostatic attraction

• between two nuclei and the share a pair of electrons

what bond joins two AlCL³ molecules together

dative covalent bonds

what is electronegativity? Then explain the polarity_, if any, of the bonds in chlorine triflorine CIF₃ (3)

• electronegativity is the ability of an atom to attract the electrons in a covalent bond

• fluorine is more electronegative that chlorine/fluorine is the most electronegative

• so fluorine is delta negative and chlorine is delta positive

explain why the melting temperature of silicon (IV) oxide is much higher than that of iodine, even though the bonding in both is covalent (3)

• silicon (IV) oxide contains many strong covalent bonds

• iodine - weak intermolecular/ london forces must be broken

• more energy is required to break the stronger bonds in silicon (IV) hence a higher melting point