C1 Flashcards
How big is the raduis of the atom?
0.1 ananometers (1x10^-10)
Descibe the structure of the atom
Nucleus:
-Protons + neutrons
-Radius= 1x10^-14
-Positive charge
-Concentration of mass
Electrons:
-Move around the Nucleus in shells
-Tiny negativly charged covers lots of space
-Virtually no mass
-Vol of orbit determins size of atoms**
What is the relative charge and mass of:
* Protons
* Neutron
* Electron
Why are atoms nutral?
-Same number of protons and electrons
-Opposite charges cancel out
Atoms have no overall charge
Whay are ions charged?
Proton number dosn’t equal number of electrons=> has overall charge
What is an ion?
Atom or group element wich has lost or gained electrons
On the nuclear symbol what does the mass number and atomic number reperent?
Mass number-> protons+ neutons
Atomic number-> protons wich are equall to electrons
What decides wich type of atom ( element) somthink is?
Protons
Same element= same protons
What is an isotope
- Diffrent forms of the same element
- same number of protons but a diffrent number of neutrons
- Same atomsic number diff mass number
What is the formular for relative atomic mass?
What is a compound? what are it’s propertys?
Subsances formed from +2 elements in fixed proportionthrought compound held together by chemical bonds
Difficult to seperate to orginal element without chemical reaction
popertys compleatly diff to original element
How are bonds made?
Atoms give away or share electrons nuclei arn’t affected by bonds made
what doses a mtal and non-metal bonding have/ consist of?
consists of ions, ionic bonding
What does a compound of non-metals consis of?
Covalent bonding sharing electrons
What is a compound? What are it’s propertys
- no chemical bonds between diff parts of mixture
- Can be made of element ore compunds
- Can be sperated vi physical processes e.g crystalisation
- Properties: mix of propertys of the seprate part
e.g. air crude oil
Describe how to do paper chromatgraphy.
1.Draw line near bottem of sheet of filter paper (pencile insoluble)
2. add ink spot to line in beaker of solvent
3. ink shouldn’t be below the solvent
4. Add lid to stop slovent evapourating
5. Solvent carrys ink up paper
6. dyes will sperate accoring to solublity insouble= stay on baseline
7. Solvent near top+ take out to dry
8. End pattern= Chromatogram
Solvent may be water or ehtnol for example
What is filteration?
- Seprate insoluble soild form liquid mixture
- Can be used to purify taking out solid impuritys
What is evapourtion?
seprate dissoved soild in liquid
1. Pour into evap dish
2. slowly heat= slovent evapourtes crystals form
3. Keep heating till you have dry crystals left
What is crystallisation?
Form solid crystals from souble solid
1.pour solution into evapourating dish
2.Gently heat slovent will evaporate the soltion will get more concentrated
3.At pont of crysalistion ( some crysatls have started to form) remove and allow subsnce to cool
4.Salt forms crystal as becomes insoulbe in the cold hightly conc soltion
5.filter crystals out and leave to dry e.g drying oven
What is simple distillation/describe it.
Used to seperte out liquid from soltion
1.soltion heated lowesr boiling poin evaps first
2.Vapour cooled condences and collected
3.rest is left in flask
- can be used to sperte pure and sea water
- only works with things of very diff boilng points
What is the frational distilation?
Seprate mixture of liquids simmilar to how crude oil is sperated
1. Put mixture in flask with fational collum onto and heat
2. diff liqids with evapourate at their boiling points
3. lowest boiling point will evap first when the temp in the thermomter reaches the boilng point it will be at the top of the column
4. Higer boiling poinst= dont reach top were cooler before condensing
5. Rase the tmep each time to get next one
How as our knowlage of the atom changed over time?
19th - soild sheres make up elements
1897- JJ Thhomson ther are charges and mases with electrons ( plum pudding)
Plum Pudding model
1897 J JThomson
Ball of postive charge with negatily charged electrons scatted throught
Descibe the observations and conclution of the gold foil scattering experiment
1909 Rutherford, alpha particles fired at gold foil
Observations:
1. Most go straight through
2. Some where deflected
3. Some deflect backwards
Concltions:
1.Most of the atom is empty space
2.Concentration of mass in nucleus
3.Concentration of mass in nucleus
Describe the nuclear model
Bohrs nuclear model
* electrons orbit nucleus in fixed shells ( fied distnace form nucleus )
* positivly charged nuclus ( no nutrons)
What was the nuclear modle?
James Chadwick
Discovery of nutrons
nuclear model
Give the genral timeline for the history of the atom
What is the rule for electrons shells?
1st: 2
2nd:8
3rd:8
How was the periodic table arranged in the early 1800s?
- Physcial and chemical properties
- Relative atomic mass
* no such thing of atomic nuber or protons at the time
element were arranged in order of atomic mass done in a periodic patterns was notice in elements
* Early table whern’t complete/in wrong group because they were place in order of relative atomic mass not properies
How did Mendeleev order the periodic table?
- 1869 Mendeleev
- Leaves gaps:
-> element of simmilar properties= same groups
->Left for some undiscovered elements= can predict some of their properties somw of wich he correctly predicted - In atomic mass but swich order if properties thought it should be changed
=>Discovery of isotopes in 20th shouldn’t place elemnts in strict order but look at properties as isotopes have diff atomic masses but same chem properies= can be same postion on periodic table
How is the modern periodic table ordered and arranged?
- Increasing atomic number wich means there are repating patterns in their properties
What are groups?
- Colums ( up an down)
- Simmilar properties
- Tells you nuber of electrons on outer shell=> all react in simmlar way
What are the periods?
- Rows
- Number of shells
What are the physical properties of metals?
all have metalic bonding causing diff physical properties:
* Strong but malleable
* Good conductors of heat+ electricity
* Hight melting+ boiling points
What are the propertries on non-metals?
- Bull
- More brittle
- Arn’t always soild at room temp
- don’t ussally conduct electrity
- Often lower density
What are the properties of transition metals?
They also have normal metal properties:
* good conductors
* dense
* strong
* shiny
Special properties:
* can have more than 1 ion
* Coloured ions
* Make good catalysts
How do metals react
not much energy is needed to remove electrons= form positive ions with full outer shells
How do non-metals react
usally share or gain ( -)
What is the trends in boiling points for group 1 metals and why?
Increaseing reactivity:
-> outer electron is more easly lost
->as the attraction between the nuclus and outer electron decreases as you go down
->Distance as between outer electron and nuclus increases
What are the qualitys of group 1 metals?
- 1 electron in outer shell= very reactive+ simmilar properties
- Soft
- Low density
What are the trends as you go down group 1?
- Increaseing reactivity
- Lowering melting/boiling points
- Higher relative atomic mass
How do alkali metals react with water?
- React vigerously to produce: Hydrogen(g)+metal hydroxides
- As you go= more reactive= more violent the reaction
- amount of energy given out as you go down increases e.g. Potassium ignites H
Metal hydroxides->salts dissolve in H20 to produce alkaline solution
How do alkaline metals react with chlorine?
- react vigrously when heated in chlorine gas forms white metal choride salts
- As you go down reactions get more vigrous
How do Alkali metals react with oxygen?
- Group 1 metal+ oxygen-> metal oxide:
- Lithium oxide
- Sodium oxide
Compaire the properties of group 1 metals and transition metals
Group 1:
* More reactive
* React more vigrously in water H20 ect
* Less dense, strong,hard
* Lower melting points
What colour & state is:
* Fluorine
* Chlorine
* Bromine
* Iodine
- Fluorine-> poisonous yellow gas
- Chlorine-> poisonous dense green gas
- Bromine-> poisonous red-brown volatile liquid
- Iodine-> dark grey solid/ purple vapour
All exist as pairs
What are the trends in group 7/Halogens as you go down?
- Less reactive-> harder to gain electrons as outer shell is futher form the nucleus
- Higher melting + boiling points
-
Higher relative atomic mass
=>All react in a simmilar way because they all have 7 outer shell electrons
What are group 0 elements?
- Full outer shell= inert
- Colourless gases at room temp
- Non-flammable
Noble gases:What is the trend in boiling points as you go down in and why?
Boiling points increase as you go down:
-> increasing number of electrons
->greater intermolecular forces wich need to be overcome
