Gcse Chemistry Paper 1 Bonding, Structure And Properties Of Matter Flashcards
Define the word compound
2 or (more) different elements that are chemically bonded together
What type of atoms form ionic compounds?
A metal
&
Non-metal
What type of atoms form covalent compound’s?
2 (or more) non-metals
What type of atoms form metallic structures?
Metals
In terms of electrons what happens in ionic bonding?
- metals lose electrons
- non-metals gain electrons
In terms of electrons what happens in covalent bonding?
Non-metal elements share electrons in pairs
In terms of electrons what happens in metallic bonding?
- metal atoms lose an electrons which becomes delocalised and can move through the whole structure.
What information does the group number tell you about an element?
The number of electrons in the outer shell
How many electrons are in the outer shell of a sodium atom?
1
One
What’s the charge of a sodium ion?
+1
Why does a sodium atom form ions with a charge of +1?
- has 1+ electron in its outer shell
- loses the electron
- to get an empty outer shell ( noble gas configuration
How many electrons are there in a chlorine atom?
7
Group 7
What is the charge for a chloride ion?
-1
Why does chlorine atom form ions with a charge of -1?
- has 7 electrons in its outer shell
- gains 1 electron ( electrons are negative)
To get a full outer shell (noble gas configuration)
Do simple molecules have high or low melting points?
Low
What state do simple molecules exist in at room temperature?
Solids,liquids or gases
Why do simple molecules have low melting and boiling points?
- weak forces
- between the molecules (intermolecular forces)
- so a small amount of energy needed to break those forces
Why do simple molecules not conduct electricity?
No overall electrical charge
Do ionic compounds have high or low melting points?
High
Why do ionic compounds have high melting points?
- giant ionic lattice
- strong electrostatic forces
- between oppositely charged ions
- so lots of energy is needed to break lots of bonds
Why do solid ionic compounds not conduct electricity?
Ions are not free to move
If you melt or dissolve a solid ionic compound it will conduct electricity why?
- ions are free to move
- and carry the current (charge)
Why do macromolecules have high melting points?
- giant covalent lattice
- all atoms are linked by strong covalent bonds
Explain why diamond is so hard
Each carbon forms 4 strong covalent bonds with other carbons forming a giant covalent structure
Explain why graphite is soft & slippery
Each carbon bonds to 3 other carbons through strong covalent bonds.
- this forms layers which can slide over each other because of weak intermolecular forces between the layers
Explain why graphite conducts electricity
1 electron on each carbon is delocalised
And can move through the whole structure
What are some of the uses in fullerenes?
- drug delivery in the body
- lubricants
- catalyst
- nanotubes for remforcing
Describe the structure of fullerenes?
Macromolecules
- made up of hexagonal rings of carbon atoms
Explain why metals are good conductors of heat & electricity
- they contain de-localised electrons
- which can move though the whole structure
Explain why metals can be easily bent and shaped?
-atoms are arranged in layers which can slide over each other
What is an alloy
A mixture of a metal and another element (usually another metal)
Why are alloys usually harder than pure metals?
Different atoms are different sizes therefore more difficult for layers to slide over each other.
What is a shape memory alloy?
A material that returns to its original shape when deformed e.g Nitinol in dental braces
How do you make low density poly ethane (ldpe)
- 200.c
- high pressure
How do you make high density poly ethane (HDPE) ?
- lower temperature
- lower pressure
- use a catalyst
Why do thermosotening polymers melt easily?
- individual tangled chains
- weak intermolecular forces between the chains
Why do thermosetting polymers do not melt easily?
-individual chains are held together by cross/links (usually sting covalent bonds)
What is a nano particle/nanoscience?
Structures that are 1-100nm
^
Nanometer
What are the features of nano particles?
- different properties to the same material in bulk ( Color,strength etc)
- high surface area to volume ratio
What are some of the uses of nano science?
- computer equipment -light & strong
- catalyst Materials
- sensors - electrical
- coatings Conductors
- cosmetics
- sun creams
