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what relative mass does a proton have
whats the relative charge of a proton
where is the proton
1
+1
nucleus
neutron
relative mass
relative charge
where is it located
1
0
nucleus
electron
relative mass
relative charge
where is it located
1/2000
-1
shell
atomic number define
mass number define
how to work out number of neutrons
number of protons
number of particles in nucleus
mass number - atomic number (top number - bottom number )
whats an ion
whats a pos and neg ion
an atom that has lost or gained electrons
positive ion= atom that has lost electrons
negative ion = atom that has gained electrons
how are elements organised
what do elements in a group have in common
what do elements in a period have in common
by the atomic number increasing
how many electrons in the last shell
configuration number gains 1
disolve meaaning
the process where a solute dissolves in a solvent to form a solution
solute define
a substance that is dissolved in a solution
solution define
solute dissolved in a solvent
mixture define
2 or more substances which arent chemically combined
solvent meaning
whats being dissolved in the solute (substance)
what are different ways of separating a solvent from an insoluble solute
filteration
evaporation (crystalation )
distilation
filteration
isotope meaning
different forms of the same element, that have the same number of protons but diff number of neutrons
chemically react the same
calculating an isotopes relative mass equation
sum of (isotope abundance x isotope mass)/ sum of abundance of all isotopes
calculate the relativve atomic mass of copper to 1 dp
copper 63 with an abundance of 69.2%
copper 65 with an abundance of 30.8%
sum of (isotope abundance x isotope mass)/ sum of abundance of all isotopes
=(63 × 69.2) + (65 × 30.8)/69.2 + 30.8
=6361.69/100
=63.6
molecule define
2 or more atoms held together by a chemical bond
can contain different or the same elements
compound define
2 or more DIFFERENT elements held together by chemical bonds
always found in the same proportions
how many atoms of each element are in H2SO4
2 Hydrogen
1 Sulfur
4 Oxygen
how many atoms of each element are in Ca(OH)2
1 Ca
2 OH
filteration
what does it do
method
separates insoluble solids from solids
put filter paper into funnel and pour mixture into it
evaporation
what dones it do
method
advantages
disadvantages
seperates a soluble solid from a solution
put solution into evaporating dish and put over budsen burner with a tripod - solvent evaporates solution more concentyrated , crystals form as solution is so concentrated
quick, easy
some solids decompsose when heated - thermal decomposition
crystalisation
what is it
method
disadvantage
seperating soluble solids from a solution which are solids suseptable to thermal decomposition
place solution into evaporating dish and heat gentkly in a water bath - when some solvent has evaporated and some crystals form stop heating and leave to cool - more crystals form as solids are less soluble at colder temps), filter crystals, and dry them in somewhere warm
slower
simple distillation
what it does
equipment
method
separates out a liquid from a solution
flask (containing solution), sealed with bung so no gas escapes, thermometer inside to measure temp, condenser surrounded by water jacket, beaker at end on condenser, Bunsen burner under flask
heat mixture so liquid we want evaporates, rises up top of flask pressure forces down the condenser and cold water through water jacket cools down the vapour condescending it into liquid collecting into beaker until all we have in flask is salt
fractional distillation
what it does
equipment
method
main techinque of sepearting mixtures of liquids
same as simple distillation but beofe going to condenser vapour goes into fractionating column
which is full of little glass rods (high surface areas), cooler at top than bottom as its so tall
heat mixture to lowest liquids boiling point so it evaporates and rises throughfractionating column and through condenser into liquid
dio the same for the next liquid and so on
its just that pure liquid in the beaker at the end as the clear rods in the reactionating column are so cold the vapour thats evapoarting turns into liquid and falls back into the mixture
When Democritus first conceived of atomic theory, around 500 BC, how did he describe atoms?(3)
Separated from each other by empty space
The smallest possible unit of matter
Small spheres
john dalton (1800s)
described the atom as (2)
solid neutral ball
different types of sypheres make up diff elements
JJ thomson (1897)
plum pudding atom
neutral solid ball of positive electrons stuffed in it
How Rutherford developed the nuclear model (4)
In Rutherford's experiments, alpha particles were fired at a thin sheet of gold foil.
Most particles passed through, but some were deflected off course.
This caused him to hypothesise that there was a dense region of positive charge at the centre of the atom that repelled the alpha particles.
As a result he developed the nuclear model of the atom, in which there was a central positive nucleus, surrounded by negative electrons.
what was the issue with rutherfords atom
what was bohrs responce (1913)
the atom should collapse as the negative electrons would be attracted to the positive nucleus, causing them to rush inwards.
electrons orbit the nucleus in shells
who discovered the neutron (20th centry)
Chadwick
who designed the periodic table
why did he leave gaps in his periodic table
dimitri mendeleev
a russian scientist in mid 19th century
for elements that had not yet been discovered (he predicted the mass and properties of missing elements)
whta is on the nuclear symbol (3)
elemental symbol (e.g Na)
bottom left - atomic number (number of protons)
top left - mass number (number of protons and neutrons)
what does each group have in common with each other
same number of electroer ns in their outershell (e.g group 1 has 1 electron in their outershell)
what do metals form when they react
non metals
positive ions
dont form ions/ negative ions
metals + non metals physical properties
metals
very strpong bonds (metallic bonding)
malluable
conductors of heat + electricity
high melting/ boiling point
shiny
non metals
dull
brittle
low melting/boiling points
low density
arent good conductors of heat
physicall properties of transitition metals
good catalysts
can form more than 1 ion
what are group 1 metals called
group 7
group 0
alkali metals
halogens
nobel gases
properties of alkaili metals
soft
low density
low melting/boiling point
as you go down group 1 do the elements get more or less reactive - why
more reactive
as they have more shells so there’s less attractive force from the nucleus to the outer shell - easier to loose the electron in the outer shell
sì melting / boiling point increase/ decrease as you go down group 1
decrease
what forms whrn an alkali metal and water react
e.g sodium
alkali metal + H2O → alkali metalOH(metal hydroxide) + H2
2Na + 2H(2)O → 2NaOH + H2
what happens when alkali metals react with chlorine
what do they form
è.g sodium
Na + Cl → NaCl
shite metal chloride salts
what happens when alkali metals react wiyh oxygen
metal oxides (type of oxide depends on the type of metal)
lithium oxide (Li(2)O
sodium oxide (Na(2)O) / sodium peroxide (Na(2)O(2)
potassium peroxide (K(2)O2) / potassium superoxide (KO2)
halogens - melting/boiling points increase or decrease
increases
halogens - reactivity increase or decrease
why
decrease
outer shell gets further away from nucleus as you go down - attractive force gets weaker so it can’t attract an electron to complete its outer shell then it can’t react
physical properties kf
fluorine
chlorine
bromine
iodine
flourine - poisoness yellow coloured gas
chlorine - green xoloured gas
bromine - red- brown volatile liquid - poisonous
iodine - grey xoloured solid wiyh purple vapor’s
what happens to the names in group 7 whrn they form ionic bonds with metals
adds a ‘D’
e.g floride, chloride, bromide, iodide
arw group 7 atoms diatomic
yes
they share atoms and form a covalent bond
how do noble gases react as
colourless gasses
inert meaning
are noble gases inert
don’t react with anything
yes - arent flammable
does boiling point of noble gases increase/ decrease as you go down the group
increase
same as halogens
what colour is
halide salts
bromide water
chlorine water
iodine water
colourless
orange
colourless
brown