2.1 Bonding Flashcards
What is the atomic number?
The number of protons in the nucleolus of an atom and the number of electrons.
What is the mass number?
The total number of neutrons and protons in a nucleolus.
What is a covalent bond?
When non-metals share one or more electrons to complete their outer shell.
- These bonds are very strong and require a lot of energy to break
What are the two main types of covalently bonded substances?
1) Simple molecules
2) Giant covalent structures
What are the properties of simple covalent substances and why they have these properties.
Low melting and boiling points- They have very strong bonds between atoms but weak intermolecular bonds between molecules which require little energy to break
What are giant covalent structures?
-A giant regular lattice (3D) containing non metal atoms that are covalently bonded to adjacent atoms
They are very strong due to the large amount of bonds.
What are the two main properties of giant covalent structures?
- Very high melting points (Large amount of bonds)
- Variable electrical conductivity- depends on structure (e.g. Graphite and Diamond)
What are allotropes and the allotropes of carbon?
Allotropes are different structures that came from the same element.
The allotropes of carbon are:
- Graphite
- Diamonds
- fullerenes (nanotubes and ‘buckyballs’)
What the structure of a diamond and what is it’s properties?
A diamond is one giant molecule made of carbon atoms that are covalently bonded to 4 adjacent carbon atoms. (Type of giant covalent structure)
-This closely packed structure makes diamonds very hard with a high melting point (making it useful in cutting tools)
other properties:
- Transparent
- lustrous (sparkles)
- not conductive of electricity
- insoluble (doesn’t dissolve in water)
What the structure of a graphite and what is it’s properties?
Each carbon atom is bonded in it’s layer to 3 other carbon atoms in a hexagonal shape which leaves 1 spare electron which together forms a ‘sea’ of delocalized electrons that conduct electricity. The layers are bonded by weak forces that can slide over one another.
Properties:
- Conductive
- High melting point
- insoluble (doesn’t dissolve in water)
- Slippery (due to the weak forces between each layer)
What is ionic bonding and the process of it?
1) An ionic bond is a reaction between a metal and a non- metal where electrons are transferred from the metal to the non-metal.
2) The metal atoms become positively charged ions and the non- mental atoms become negatively charged ions.
3) There is then a strong electrostatic force between these charged ions that bond them together- this is called an ionic bond.
- This results in an ionic compound
What is a giant ionic structure?
A regular ionic lattice (3D) with alternating positive and negative ions.
What is the structure and properties of a metal?
They are made up of a regular arrangement of positive metal ions with a ‘sea’ of delocalized electrons.
Malleable- can be moulded or hammered into shape easily
Ductile- Can be stretched into a wire because the layers of ions can slide over each other.
Conductive of heat and electricity- the ‘sea’ of delocalized electrons allow vibrations or electricity to be passed from one side to the other.
High melting and boiling points- the strong electrostatic forces of attraction between negatively charged electrons and positively charged ions takes a lot of energy to overcome.
What is a nano-particle?
A nano-particle is a particle that us 1- 100 nm in size (1x10^9) . These particles can have very different properties to the ‘normal’ sized substances.
What do silver nano-particles do and what are the uses?
Kills bacteria and viruses.
- Wound dressing to prevent infection
- deodorants/ air spray that kills bacteria that cause bad smells
- Disinfects water (like on the ISS)
