chemistry paper 1- atoms Flashcards
RP for paper chromatography
draw a line at the bottom of the filter paper
using a pencil- as it is insoluble and won’t dissolve in the solvent
add a spot of ink to the line and place in beaker of water
make sure the ink doesn’t touch the water
place lid on top to prevent evaporation of water
the water will seep up carrying ink with it
each dye will move at different rates and spread out forming a spot
if these are insoluble they’ll stay on the baseline
leave to dry when the water reaches the top
the pattern = chromatography
What is the process of filtration?
separates insoluble solids from liquids
filter paper is folded and the solid is left on the paper - this is the residue
what is a way that you can separate insoluble solids from liquids?
filtration
What way can you separate soluble solids from solutions?
evaporation + crystallisation
What is the process of evaporation?
pour solution into the dish
heat the solution and the solvent will evaporate and get more
concentrated = crystals start to form
what is the process of crystallisation?
pour solution into the dish and heat up
solvent will evaporate and get more concentrated
remove solution from the heat and cool
filter the crystals and leave them in a warm place to dry
(u can use a drying oven)
simple distillation RP
-used to separate out a liquid from a solution with very different BP
solution is heated : the part with LBP evaporates first
vapour is then cooled, condenses and then collected
rest is left behind in the flask
simple distillation includes: water evaporates condensed and collected, ending up with salt left in flask
what’s the problem with simple distillation?
you can only use it to separate things with very different boiling points
if temp goes higher than BP of the substance they will mix again, not seperate
fractional distillation RP
-used to separate mixture of liquids with similar BP
put mixture in flask and put fractionating column on top + heat it
different liquid have different BP so they evaporate at different temp
lowest BP evaporates first
when the thermometer temp and liquid temp match - it reaches the top
liquid with higher BP will get part of the way up before condensing + running down to the flask
when the first liquid is collected raise temp until next one reaches the top
John Dalton’s Theory
atoms were solid spheres making up different elements
JJ Thomson’s Theory
Plum Pudding Model:
ball of positive charge with electron in it
Ernest Rutherford’s Theory
Nuclear model:
positively charged nucleus in the centre + cloud of negative therefore there’s mostly empty space
Neil Bohr’s Theory
electrons orbit and are contained in shells
what did james chadwick discover?
neutrons
what did rutherford discover?
protons
what did jj thomson discover?
electrons
Periodic Table before Dmitri Mendeleev?
-categorised by physical and chemical properties
-atomic weight
Dmitri Mendeleev’s Periodic Table?
- mainly in order of atomic weight but changed it if needed
-gaps were left so elements with similar properties stayed in the same group
Electronic structure of metals
don’t have many electrons to remove
are further away from the nucleus
weaker attraction
not much energy is needed to remove the electrons
Electronic structure of non-metals
they have lots of electrons to to remove
stronger attraction
better to share/gain electrons
to get a full outer shell
properties of metals
strong
high bpt and mpt
good at conducting heat + electricity
properties of non-metals
brittle
dull
don’t conduct electricity
Group 1 Elements
ALKALI
one electron in the outer shell
very reactive - soft
As you go down:
increase in reactivity as the outer electron can easily get lost as its further away so weaker attraction
low bpt and mpt
high relative atomic mass
what happens when group 1 metal are put in water
react vigorously, fizzing
produce hydrogen gas : energy given out increases as u go down
