Chemistry Topic 2 - Bonding, Structure and Properties of Matter Flashcards
Ions are made when…
Electrons are transferred
Define Ions
Charged Particles
When metals form ions…
They lose electrons and form positive ions
When non-metals form ions…
They gain electrons and form negative ions
What happens in ionic bonding
metal atom loses electron to form positive ion and non-metal gains electron to form negative ion. these oppositely charged ions are strongly attracted to one another by strong electrostatic force of attraction
Describe the structure of an ionic compound
The ions form a closely packed Regular Lattice Structure and they have very strong electrostatic forces of attraction between oppositely charged ions in all directions.
Ionic compound properties (3 marks)
. High melting and boiling point due to strong bond
. When solid ions are held in place so cannot conduct eletricity
. When melted, ions seperate and are free to move and carries electric current and conduct electricity
What happens in Covalent bonding
Bonding between non-metals where they share a pair of electrons to make covalent bonds.
Why is Covalent Bonds strong
The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic force of attraction making them strong
Why do atoms want to have a full outer shell
it gives them electronic structure of noble gases, which is very stable.
What has a simple molecular structure
Substances containing covalent bonds
Properties of simple molecular substances
Dont conduct electricity because they arent charged so no free electrons or ions
As they get bigger, melting and boiling point increases because intermolecular forces increase so more energy required to break them.
In which state are most simple molecular substances at room temp
Liquids and Gases
What forces need to be overcome to boil a simple molecular compound
Intermolecular forces need to be overcome
What are polymers
Long chains of repeating units joined by strong covalent bonds
What state are polymers at room temp
Solid
Diamond
Each carbon atom forms four covalent bonds
Graphite
Each carbon atom forms three covalent bonds
Allotropes of Diamond (3 marks)
Giant covalent structure which makes Diamond strong
Diamond has a very high melting point as it requires a lot of energy to break Diamond
Does not conduct electricity because it has no free electrons or ions
Allotropes of Graphite (3 marks)
No covalent bonds between layers so they are free to move over each other which makes graphite soft and slippery
High melting point
Conducts electricity and thermal energy
Why does Graphite conduct electricity
For each carbon atom has one delocalised electron and can move
Why is Graphite a good Lubricating material
Graphite is held together weakly so is soft and slippery so is an ideal lubricating material
What is Fullerene
molecules of carbon which forms spheres and tubes
Properties of Fullerene
Huge surface area.
Make great lubricants
Can be used to cage other molecules which can be used to deliver drugs into body
What is Graphite
Sheets of carbon atoms arranged in hexagons
Metallic bonding
Bonding between metals. Formed between positively charged atoms in which there is a sea of delocalised electrons moving around in the lattice structure.
Why are metals solid at room temp
There is a strong electrostatic force of attraction between metal atoms and delocalised electrons so needs a lot of energy to be broken. this means it has a high melting and boiling point
Why are metals a good conductor of electricity and heat
The delocalised electrons carry electrical current and thermal energy through the whole structure
Why are metals malleable
The layers of atoms in a metal can slide over each other
What are Alloys
a mixture of 2 or more metals or a metal and another element
