C3. Atoms, elements and compounds Flashcards
properties of covalent compounds
low boiling point - weak intermolecular attractive force
insoluble in water
does not conduct electricity - no ions
properties of ionic compounds
high boiling point - strong attractive force
soluble in water but insoluble in organic solvent
conduct electricity when molten - ions are mobile when molten x ions are packed together and not free to move
define isotopes
atoms of the same elements with different number of neutron
mixture
2+ mixture that are not chemically bonded
what is the attractive force between molecules
intermolecular forces
structure of diamond
a carbon atom forms four covalent bonds with other carbon atoms
structure of graphite
arranged in layers
each carbon atoms is joined by three other carbon atoms
why graphite is used as lubricants
the bonding between the layers in graphite is weak
-> layers can slide past each other
describe a metallic structure
lattice of +ve charged metals ions
surrounded by a sea of free, delocalised electrons
what is metallic bonding
the electrostatic attraction between the electrons and metal ions
structure of silicon(IV) oxide
each silicon atom is bonded to four oxygen
properties of silicon(IV) oxide
high boiling point - strong covalent bonds
does not conduct electricity - has no delocalised electrons
