Chemistry level 6 - Lectures 3 and 4 Flashcards
what is covalent bonding?
sharing of electrons between non-metals to allow formation of stable electron arrangements
what are the types of structure that form due to covalent bonding?
molecular and networks
what are examples of discrete covalent molecular gas
the halogens and diatomic molecules
what are unusual covalent elements?
- phosphorus (P4)
-sulphur (S8)
what are examples of discrete covalent molecular compounds?
- hydrogen chloride
- water
what are the intermolecular forces between discrete molecules called?
Van der Waals forces
what are examples of covalent networks?
- diamond
- graphite
- silicon dioxide
- silicon
what are the properties of diamond
- very high melting point
- does not conduct electricity
- not soluble in water
- strong and rigid
what are properties of graphite
- weak and brittle
- delocalised electrons between layers, so can conduct electricity
- not soluble in water
what are properties of silicon
- strong and rigid
- very high melting point
- does not conduct electricity
- not soluble in water
what are properties of silicon dioxide
- very strong and rigid
- very high melting point
- does not conduct electricity
- not soluble in water
how are noble gas arrangements achieved in ionic bonding?
by gaining or losing electrons
what are ions?
electrically charged particle
what is ionic bonding?
electrostatic force of attraction between oppositely charged ions
what structure is formed in ionic bonding?
ionic lattice
what are properties of ionic bonding?
- high melting and boiling points
- soluble in water
- CAN conduct electricity depending on state
why can solid ionic compounds not conduct electricity?
because the ions are not free to move to carry an electric current
why can ionic compounds that dissolve or melt in water conduct electricity?
because they ions are free to move
what structure forms in metallic bonding?
crystal lattice that consists of stationary ions surrounded by a ‘sea of electrons’
what are properties of metallic bonding?
- high melting and boiling points
- conducts electricity
how can metallic bonds conduct electricity?
because the delocalised electrons can carry the charge of an electric current when voltage is applied across a piece of metal
