Nature of covalent and dative covalent bonds

which atoms are involved in covalent bonding?

non-metals

how does covalent bonding occur?

electrons are shared

what keeps the bonds together?

electrostatic attraction between the shared electrons and positive nuclei

what is a dative/co-ordinate bond?

both electrons are from the same atom. it behaves like a normal covalent bond once formed

how do you represent dative/co-ordinate bond?

with an arrow to show both electrons have come from one atom

what structure are molecules like O₂ and I₂ ?

simple molecular

what state are simple molecular usually at room temp? Why?

gas, as they have weak intermolecular forces that do not require much energy to break

Can simple molecular conduct electricity? Why?

no, as there are no charged ions/particles to carry charge

give some examples of giant covalent structures?

• diamond

• graphite

• graphene

what are all these giant covalent structures an example of?

allotropes of carbon

what determines a giant covalent structures’ properties?

their bonding

describe diamonds structure and properties?

• millions of carbon atoms

• each one is bonded to 4 others in a tetrahedral shape

• hard due to strong covalent bonds between atoms

• does not conduct as there are no free electrons to carry a charge

describe graphite’s structure and properties of bonding:

• each carbon is bonded to 3 others - forms hexagonal layers

• layers are joined with weak intermolecular forces

• soft as the forces can easily be broken

• can conduct due to spare electron on each carbon which becomes delocalised and can move between layers and can carry the charge

what does macromolecular mean?

giant molecular structures

what are the 4 types of crystal structure?

• ionic

• metallic

• macromolecular (giant covalent)

• molecular