Chemistry - Bonding, structure and properties of matter

Metalic bonding

occurs because electrons move freely among a metals positively charged ions and explains properties such as ductile and the ability to conduct electricity.

Structure of metals

giant lattice (regular pattern)

Why do metals have high melting points

They have strong electrostatic attractions between the ions and electrons

Why are metals good conductors of electricity?

Because the delocalised electrons in the metal carry an electrical charge through the structure

Why are pure metals malleable?

Because layers of atoms in metals are able to slide over each other

Properties of metals

Malleable, Ductile and Good Conductors of Heat and Electricity

Why are metals dense?

Metallic lattices are closely packed

How does Metallic Bonding work?

Positive metal ions are held together outer shell electrons which become delocalised

Ionic bonding

The electrostatic attraction between oppositely charged ions

How does ionic bonding work?

-An electron is stolen from the metal and is transferred to the non-metal

-ions form

-ions stick together

ions

electrically charged atoms that have either gained or lost electrons.

Properties of ionic bonding

high melting and boiling point

high soluable

high degree of brittleness

Why do ionic compounds have high melting points?

Strong electrostatic attraction between the positive and negative ions requires a lot of energy to overcome.

Do ionic compounds conduct electricity?

Only when molten or dissolved in water

Why do ionic compounds only conduct when molten or dissolved

Because in a solid, the ions can't move

However, in liquid form, the ions can move and carrya charge

Solution

A mixture that forms when one substance dissolves another.

Solute

A substance that is dissolved in a solution.

Structure of ionic compounds

Giant lattice of oppositely charged ions

Covalent bonding

a bond formed when atoms share one or more pairs of electrons (non metals only)

How does covalent bonding work?

Electrons are shared between non-metal electrons. they are held together by the electrostatic attraction between the positive nucleus and negatively charged bonding region

structure of covalent compounds

simple molecular structure

Properties of covalent bonding

- Low melting and boiling points

- Do not conduct electricity

Why can't Covalent Molecules conduct electricity ?

Covalent Molecules can't conduct electricity because they don't have an overall electric charge

Why do covalent structures have a low melting point

The intermolecular forces between the molecules are weak

Allotropes

different molecular structures of the same element

allotropes of carbon

diamond, graphite, fullerene

transition metals

Elements that are located in groups 3 -12 on the periodic table

Properties of transition metals

good conductors of heat and electricity

Structure of diamond

3D tetrahedral structure of C atoms, with each C atom bonded to four others

Properties of diamond

-tetrahedral shape, crystal lattice structure

-high melting point

-hard (tipped drills/saws)

-good thermal conductor

-can't conduct electricity

-insoluble in any solvent

Why does diamond have a high melting point?

There are strong covalent bonds between atoms that are hard to break

Why are diamonds hard?

The carbon atoms are bonded in 4 directions and evenly spread the load of the force.

Why doesn't diamond conduct electricity?

It has no free electrons or ions

Graphite

black form of carbon used in lead pencils

Structure of graphite

Each carbon atom bonded to 3 other carbon atoms. Layers of hexagonal rings of carbon atoms. Weak intermolecular forces between layers. One delocalised electron per carbon atom.

Properties of graphite

-Soft

-Slippery

-high melting point

-good conductor of heat and electricity

Why does graphite conduct electricity?

one electron from each carbon atom is delocalised so can carry current through the substance

Why does graphite have a high melting point

The covalent bonds in the layers need loads of energy to break

Why is graphite soft and slippery?

Graphite is formed in layers, there is no covalent bond between the layers and so the layer can slide over each other, making graphite slippery

Graphene

This is a single layer of graphite.

properties of graphene

- Conductor of thermal energy and electricity

- low density

- It is the most reactive form of carbon

- Pieces are incredibly strong for their mass

Fullerenes

Molecules of carbon atoms with hollow shapes.

Their structures are based on hexagonal rings of carbon atoms, and may also contain rings with 5 or 7 carbon atoms.

What are fullerenes used for?

- used to deliver drugs in the body

- in lubricants as catalysts

- for reinforcing materials

Properties of fullerenes

-3 bonds for each carbon

-conducts electricity

-hollow

nanoparticles

particles between 1 and 100 nanometers in size

Properties of nanoparticles

Large surface area to volume ratio, react very quickly.

Carbon nanotubes

cylindrical fullerenes with very high length to diameter ratios

What are carbon nanotubes used for?

-nanotechnology

-tennis rackets

-electronics

-reinforced materials

buckminster fullerenes

Allotropes of carbon with at least 60 carbon atoms shaped like a soccer ball or geodesic dome.

What are nanoparticles used for?

-medicines

-electronics

-cosmetics

-catalysts

-suncream

-antibacterial coatings

risks of nanoparticles

- can enter atmosphere and damage lungs

- enter bloodstream through cosmetics

- easily explosives

- aquatic life could be damaged by washing clothes with them