3.1.3.4 bonding and physical properties

What are the 2 types of covalent substances

Molecular

simple molecular

Macro molecular

giant covalent

What is iodine and ice an example of

Molecular covalent crystals

What is the bonding like in molecular covalent crystals

In molecular covalent crystals

The bonding within the molecules is covalent but the bond between the molecules is intermolecular forces

What are the properties of molecular covalent crystals (3)

Low M.P (weak intermolecular bonds between molecules)

Brittle- dont have strong bonds holding them together unlike ionic crystals or diamonds)

Don’t conduct electricity

What are the 2 examples of macro molecular

Diamond nd graphite

Diamond and graphite are examples of

CARBON

What differs between diamond and graphite

The way they are bonded

What is the definition of alllotrpes and what are the allotropes of carbon

allotropes are different forms of the same element in the same form

The allotropes of carbon are diamond and graphite

What are 4 properties of diamond

Very strong due to strong covalent bonds and rigid 3d structure

High m.p (many covalent bonds)

TETRAHEDRAL each carbon is bonded to 4 others (bond angle is 109.5)

No conduction of heat or electricity as there are no charged particles that are moving)

What is a use of diamond

Cutting glass

How is graphite arranged what is the shape and b.a

¾ of the carbons are bonded to carbon so there is one delocalised electron

Bonded in a hexagonal arrangement and bond angle is 120 degrees

What are some properties of graphite

Conducts electricity (delocalised electrons between layers

High m.p strong c.b between layers

Weak forces of attraction between layers so they slide over (FLAKINESS)

What is one use of graphite

Used in pencil lead

Which processes of changing state is energy taken in

Melting

Boiling

Which processes is energy released

Freezing

Condensing

What 2 substances sublime

Solide iodine

And solid carbon dioxide (called dry ice)