Chemistry

• three states of matter are liquid, solid and gas
• atoms can share or transfer electrons to form chemical bonds
• a covalent bond is where electrons are shared between non metal atoms
• the amount of energy needed to change the state of a substance depends on the force between particles
• the stronger the forces between particles, the higher the melting or boiling point.
• a giant covalent has billions of atoms
• a giant covalent has a strong bond
• an example of a giant covalent is a diamond
• small molecules contain a few atoms
• small molecules have strong covalent bonds
• different molecules are held together by weak intermolecular forces
• water is made of small molecules
• large molecules realest until forming a chain
• polymers are an example of long molecules
• covalent bonds are formed by atoms sharing electrons
• non metals form covalent bonds between them
• giant substances have high melting points as a small amount of energy is needed to break down the bonds
• graphite is one layer of graphene
• fullerene is a hollow cage of carbon atoms prestented as a sphere or tube
• graphite is strong and conducts electricity
• giant covalent have high melting and boiling points
• small molecules have low melting and boiling points
• large molecules have low melting and boiling points
• most covalent structures don’t conduct electricity
• graphite is a giant covalent
• graphite is only made of carbon
• graphites delocalised electrons allow free movement
• fullerenes conduct electricity
• fullerene has 60 carbon atoms
• graphine is used in high tech electronics
• the carbon atoms in nano tubes are arranged in cylindrical tubes
• nanotubes have high tensile strength
• ions are atoms that has lost or gained electrons
• metals and non metals form ionic bonds
• the electostatic force of attraction holds oppositely charged ions together
• ionic substances have high melting points as the electrostatic force of attraction has lots of energy holding positive and negitive ions
• ionic substance conduct electricity when melted as the ions become free
• pure metal has strong electrostatic forces
• metals are malleable as layers slide over each other easily
• an alloy is a mix of metal with atoms of another element