Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
What is the mass number of an element? |
The number of neutrons + the number of protons |
|
What is the atomic number of an element? |
The number of protons in an element ( alsot he number of electrons) |
|
What are the relative masses and relative charges of the subatomic particles? |
Particle Charge Mass Proton +1 1 Neutron 0 1 Electron -1 1/2000 |
|
How do you work out the number of neutrons in an element? |
Atomic mass - atomic number of an element |
|
What are chemicals? |
When two or more elements are chemically bonded together though a chemical reaction and are difficult to separate |
|
What is an isotope? |
Different atomic forms of the same element with the same number of protons (atomic number) but a different number of neutrons (atomic mass) |
|
How does ionic bonding work? |
Occurs between a metal and a non-metal Atoms lose of gain electrons to form ions with a charge that are strongly attracted to each other as they have opposite charges |
|
How do metals ionically react? |
They only have one or two electrons in their outer shell so they are in group 1 or 2 They try to lose those one or two electrons to gain a full outer shell of electrons The gain + charges |
|
How do non- metals ionically react? |
They have 6 or 7 electrons in their outer shell so they re in group 6 or 7 The try to gain 1 or 2 electrons to gain a full outer shell They gain - charges |
|
What is the form of an ionic compound? |
It forms a giant ionic lattice They have a regular arrangement There are very strong electrostatic forces of attraction between oppositely charged ions |
|
What are the properties of ionic compounds? |
They have high melting and boiling points ( lots of strong bonds require a lot of energy to break) When melted or dissolved they can conduct electricity as their ions are free to move through the substance and carry the current |
|
How does covalent bonding work? |
Two non-metals share electrons in their outer shells to each gain a full outer shell |
|
What are the properties of simple molecular structures? |
These atoms form very strong covalent bonds to form simple molecules They have low melting and boiling points as the intermolecular forces between molecules are very weak and easy to break Mainly gases or liquids at room temperature Don't conduct electricity -no charged particles |
|
What are the properties of giant covalent structures? |
All the atoms are bonded together by strong covalent bonds They have high melting and boiling points Don't conduct electricity |
|
What is the bonding in Diamond? |
Each carbon atom is bonded to four other carbon atoms This forms a rigid structure Therefore it doesn't conduct electricity |
|
What is the bonding in Graphite? |
Each carbon atom is only bonded to 3 other carbon atoms Therefore there is one free carbon atom which has a delocalised electron allowing it to conduct heat and electricity It exists in hexagonal layers which slide over each other as there are weak intermolecular forces |
|
What is the structure of a metal? |
Positive ions in a giant structure with a sea of delocalised negative free electrons There are strong metallic bonds between the positive ion and the negative electron The electrons allow it to conduct electricity and hold the regular structure so layers can slide |
|
What are alloys and why are they harder than pure metals? |
They are a mixture of two or more metals They have different sized atoms distorting the layers so they can't slide |
|
What are smart materials? |
Materials which behave differently depending on conditions such as temperature For example nitinol can be used in dental braces and when cooled can be remoulded and then when reheated it remembers this shape and tries to return to this shape pulling your teeth |
|
What are nanoparticles? |
Particles less than 100 Nm across They can be used in sensors and makeup as they have a high surface area to volume ratio |
|
What are fullerenes? |
Molecules of carbon that are shaped in tubes in hexagonal rings They an be used for reinforcements as the covalent bonds are very strong |
|
What is a thermo-softening polymer? |
A polymer made of individual polymer chains held together by weak intermolecular forces They don't have cross links so can be melted and remoulded easily |
|
What is a thermosetting polymer? |
A polymer made of polymer chains joined by cross links giving strong intermolecular forces They can't be melted or remoulded |
|
How can you change the properties of a polymer? |
You can change the starting materials Conditions LD polythene - hot temperature + high pressure HD Polythene - low temperature + low pressure + catalyst |
|
What is relative atomic mass? |
The relative mass of an atom compared with the mass of one atom of carbon-12 Same as the mass number |
|
What is the relative formula mass? |
All of the atomic masses in a compound added together |
|
What is a mole? |
The relative formula mass of a substance in grams = Mass / RFM |
|
How to work out percentage mass of an element in a compound? |
Ar X No of atoms |