Structure Flashcards
(19 cards)
What type of structure is ionic?
giant lattice
Do ionic substances have a high melting & boiling point?
yes
- lots of energy required to overcome strong electrostatic attractions between oppositely charged ions
- giant so lots of ionic bonds
Do ionic substances conduct electricity?
no
- ions are fixed in place & can’t move
Do ionic substances conduct electricity when molten or aqueous?
yes
- ions are now free to move & carry the charge
What is ionic bonding?
strong electrostatic attraction between oppositely charged ions
What is covalent bonding?
strong electrostatic attraction between positive nuclei of each atom & negative shared pair of electrons
What type of structure is covalent?
giant or simple
Do covalent substances have a high melting & boiling point?
simple: no
- weak intermolecular forces do not require lots of energy to overcome
giant: yes
- many strong covalent bonds that require lots of energy to overcome
Do covalent substances conduct electricity?
no
- no delocalised electrons, not made up of ions
What are the properties of diamond?
- each carbon is bonded to 4 other carbons, so tetrahedral structure
- very hard - lots of energy is needed to overcome strong covalent bonds
- doesn’t conduct electricity - no delocalised electrons that can move
What are the properties of graphite?
- every carbon is bonded to 3 other carbons to form sheets of carbons
- soft (used in pencils & as lubricant), weak forces hold layers together, so layers slide over each other easily
- does conduct electricity due to sea of delocalised electrons that can move
What is metallic bonding?
strong electrostatic attractions between positive metal ions & sea of delocalised electrons
Do metallicly bonded substances have a high melting & boiling point?
yes
- giant structure - many strong electrostatic forces of attraction between positive metal ions & sea of delocalised electrons that require a lot of energy to overcome
What type of structure is metallic?
giant
Do metallicly bonded substances conduct electricity?
yes
- sea of delocalised electrons can move - a current can travel through
Malleable
easy to shape, layers of ordered positive electrons slide over eachother easily
Ductile
Can be pulled into wires, layers of ordered positive electrons slide over eachother easily
What is an alloy?
mixture of elements where at least 1 is a metal
What properties do alloys have?
- different sized atoms added to structure
- distorts layers in metal
- layers can’t slide over eachother as easily
- alloys are stronger, harder & less malleable
