covalent bonding

define covalent bonding

the electrostatic attraction between a shared pair of electrons and positive nuclei

in a covalent dot and cross diagram, how many electrons must there be in total (except hydrogen) in the outer shell?

8wh

which kinds of elements are covalent bonds formed between?

non metals

which elements form diatomic molecules naturally?

oxygen

nitrogen

iodine

fluorine

bromine

chlorine

hydrogen

which two types of covalent structures are there?

simple molecular

giant covalent lattice

melting point of simple molecular structures

low as there are weak intermolecular forces between molecules which need little energy to overcome

melting point of giant covalent compounds

high as strong covalent bonds need lots of energy to break

electricity conduction of covalent compounds

never as they contain no charged particles (electrons/ions) which are free to move and carry charge

what state are most covalent compounds at rtp?

gases

what are the general physical properties of giant covalent compounds?

hard (except graphite) as strong covalent bonds require lots of energy to break

name 3 covalent compounds formed entirely from carbon

diamond

graphite

buckminster fullerene

properties of diamond

hard - strong covalent bonds require lots of energy to break

can’t conduct electricity

high mp/bp

properties of graphite

soft

conducts electricity

how many carbon atoms is each carbon atom bonded to in graphite?

3

why is graphite soft?

it is formed in layers which have weak intermolecular forces of attraction between them, which are easily broken, and thus the layers can slide over each other

why can graphite conduct electricity?

as each atom is only bonded to three others there is a free delocalised electron from each atom which can move and carry charge

what shape is buckminsterfullerene?

ball - balls don’t break

is diamond soluble in water?

no - solvation releases less energy than is needed to break the strong covalent bonds