3.1.1.3 Metallic Bonding & Melting Point Flashcards
What is metallic bonding
Its the electrostatic interactions between positive metal ions and delocalised electrons
How are the atoms in metallic bonding
they are ionised:
> Positive ions occupy fixed position in a lattice
> the outer shell electron are delocalised - they are shared between all the atoms in he metallic structrure
What are the three properties of giant metallic structure?
> High melting & boiling point
Good electrical conductor
Malleable & Ductile
Describe giant metallic structure as having high melting & boiling point
Due to the attraction between the positive ions and negative electrons therefore high temp is needed to overcome the metallic bonds
Describe giant metallic structure as a good electrical conductor
as delocalised electrons can move anywhere within the lattice, allowing the current to flow
Describe giant metallic structure as Malleable & Ductile
as the atoms are able to roll over one another and go into a new position without breaking the metallic bond.
How are solid giant covalent lattices of carbon ( Diamond, Graphite and graphene) and silicon bonded by?
They are networks of atoms bonded by strong covalent bonds
What structure do period 2 & 3 elements have Li, Be, Na, Mg, Al
> Structure: Giant metallic
Forces: Strong attraction between the positive ions and negative electrons
Bonding: Metallic
What structure do period 2 & 3 elements have B, C, Si
> Structure: Giant covalent
Forces: Strong forces between atoms
Bonding: Covalent
What structure do period 2 & 3 elements have N2, O2, F2, Ne, P4, S8, Cl2, Ar
> Structure: simple molecular
Forces: Weak intermolecular forces between molecules
Bonding: Covalent bonding within molecules, intermolecular bonding between molecules
What happens to the melting point between group 1 and 14?
Melting point increases as they have giant structures.
> If an element has a giant metallic structure the Nuclear charge increases & the number of electrons in the outer shell which causes a stronger attraction
> If it has a giant covalent lattice, each successive group has more electrons with which to form covalent bonds
What happens to the melting point between group 14 and 15?
Decrease in melting point. This is because the element have simple molecular structures - each individual molecule is attracted to other by relatively weak intermolecular forces
What happens to the melting point between group 15 and 18?
The melting points remain relatively low - the element have simple molecular structures
