chemistry test Flashcards
plum pudding model
sphere of positiv charge with small negative charges disrtibuted evently within it
rutherfords electron shell model
small dense central nucleus surrounded by orbiting electrons
nucleus = protons and neutrons giving overall pos charge
maximum number of orbiting elsesctons in a single shell
2n2
mass number
represented using a
protons and nuetrons
atomic number
z
number of protons in the atom
Ar
the mean mass of an atom of an element divided by one twelfth of the mean mass of an atom of the carbon 12 isotppe
isotope
atoms of the same elemtn with the same atomic number but diff neutron numbets resulting in diff mass number
react chemicaly in the same way as electron config is the same
diff mass number= diff physucal properties
ions
formed when an atom loses or gains electrons mesning it is no longer neutral and will have an overall charge
what is mass spectrometyr
this is an analytical techniques used to identify different isotpes and find the overall relatve atmic mass of an element
TOF steps
ionsiation
acceleration
ion drift
detection
analysis
ionisation
vapourised injected into mass spectrometer
high vltage
electron removed
+1 ion
acceleration
pod charged ions accelrated to neg charged detection plate
io drift
magnetic field deflects
detection
ion hits neg charged plate gain electron proudcong flow charge
greater abundance greater currwnt produce as they are propotional
analysis
flightimes to produce a spectra print out with relative abundance of eavh isotopes displayed
ar from spectra
m/z x abundance/ total abundance
orbitals
electeons are held in clouds of negative chsrge called orbitals
s p d f
s orbital shape
spherical
p orbital shape
dumbbell
d orbital
clover
electrons in s
2
electrons in p
6
electrons in d
10
spin
electrons pair up with opp spin so atom is as stavle
electrons same orbital opposite spin
ionisation energy
the minimum energy required to remove one mole of electrons from one mole of atoms in gaseous state
sucesseive ionisation energy
occurs when further elecons are removed
requires more energy because as electrons removed electrostatic forces of attraction between pos nucleus amd outer electron inc
more energy needed to overocme lo
ionisation energy along a period
increases due to decreasing atomic radius and greater electrostatic forces of attraction
ionisation energy down a group
firstnionisation energy decreases due to an increasing atomic radius and shielidng which reduces the effect of the electrostatic forces of attaraction
first ionisation of aluminium
lower than expected
single psir of electrons with opposite spin
natural repulsion
reduces amount of energy needed to be put to remove eletron
atomic radius a long a period
decreases
increased nc
outer electrons pulled in closer
greater attraction
more shells more shielding
nucleur attraction reduced
ionisation energy along a period
increases
decreasing atomic radius
inc nc
outershelll celectrons held more strongly and therefroew more energy required to remove them
ionisation energy downa group
decreases
nuclaur attraction between nucleus and outer slectron reduces
inc cheilding
less energy needed to remove
melting points in group 3
sod mag al -metallic bonding
mp inc due to pos charged ions
attractive forces increase from Na to Al
sillicon
macromolecuslr
stong covslrnt strucutre
lots
more energy do over come
phopshorus sulfur chlorine
simple covslnt
weak van der waals
dont require much energy to overcome
low similar mps
why argon is a gas at room temp
full outershell
stable
weak vdw
low mp
exists as gas at rtp
ionic bonding
metal and non
electron from metal to non
creates ions
oppositely charged afftravt thrpugh electrostatic forces to for, a giant ionic lattice
covalent bonding
two non metals
electrons shared
dative covalent bond
both electrons in the shared pair are supplied from a single atom
inducated using an arrow from lone pair
metallic bond
lattice of posotfily charged ions surrounded by sea delocalised electrons
strong forces of elecrtostatic attraction
larger ion larger radius weaker attraction
ionic properties
high mp and bp
lots energy needed to overvome electrostatic forces in alttice
moletn or aq sol conduct ekectricity
free moving ions
brittle
metallic properties
confuctors
sea
carry flow of charge
malleable
slide layers
solid at room temp
macromolcue properties
covalently bonded giant lattice
multiple covsneltn bofs
high mp
strong covalent latticr so rigid
diamond
bonded to four other carbon atoms
graphite
3 other carbons
flat sheets
free electrons
move betwen layers
conduct electricity
simple molecule
eg.iodine
covalnetly bonded
weak vdw
low mp and bp
poor cnducotrs
lone pair repulsion
additional repulsive forces changes bond angle reduced by 2.5
linear
bonding pairs
lone pairs
bond angle
2
0
180
v shaped
bonding pairs
lone pairs
bond angles
2
2
104.5
trigonal planar
bonding pairs]
lone pairs
bond angles
3
0
120
triagnular pyramid
bonding pairs
lone pairs
bond angles
3
1
107
tetrahedral bonding pairs
lone pairsn
bond angles
4
0
109.5
trigonal bipyramid
bonding pairs
lone pair
bond angles
5
0
90 and 120
octahedral
bonding pairs
lone pairs
bonf angles
6
0
90
electronegatvitiy
the power of an atom to attract negative charge towards itself in a covalent bond
permanant dipole
two atoms with diff electronegativities polar bond formed
more electroneg atom draws more neg charge towards itself away from other atom
induced dipole
when electron orbitalare influenced by another charged particles
vdw
weakest
induced dipole between molecules
larger mr stronger imf
straight chains stronger cdw pack closely together
permanant dipole
polar bond
attarct eachither
alltice structure
hyrodgen bonding
fon
lone pair on these atoms forma. bond with a hydorgen atomfrom another molecule shown witha dotted line
high mp and bp
The size of the first ionisation energy is affected by four factors:
Size of the nuclear charge
Distance of outer electrons from the nucleus
Shielding effect of inner electrons
Spin-pair repulsion
between beryllium and boron
fifth electron in boron is in the 2p subshell, which is further away from the nucleus than the 2s subshell of beryllium
Beryllium has a first ionisation energy of 900 kJ mol-1 as its electron configuration is 1s2 2s2
Boron has a first ionisation energy of 800 kJ mol-1 as its electron configuration is 1s2 2s2 2px1
between nitrogen and oxygen
decrease in IE1
spin-pair repulsion in the 2px orbital of oxygen
Nitrogen has a first ionisation energy of 1400 kJ mol-1 as its electron configuration is 1s2 2s2 2px1 2py1 2pz1
Oxygen has a first ionisation energy of 1310 kJ mol-1 as its electron configuration is 1s2 2s2 2px2 2py1 2pz1
In oxygen, there are 2 electrons in the 2px orbital, so the repulsion between those electrons makes it slightly easier for one of those electrons to be removed
The successive ionisation energies of an element increas
As more electrons are removed, the attractive forces increase due to decreasing shielding and an increase in the proton to electron ratio
oxides from period 3 elements
sodium oxide
magnesium oxides
aluminium oxides
sillicon dioxide
phopshopurs oxide
sulfur dioxide
sulfur trioxide
sodium oxide oxidsiton state
1
magneisum oxide oxidation state
2
alumiunm oxide oxidation state
3
sillicon dioxide oxidation statae
4
sulfur trioxide oxidation state
6
na2o structure and bonding and reactivity
ionic
vigorous
mgo structure and reactivity
ionic
vigorous
Al2o3
ionic
slow
sio2
macromolecular
slow
p4o10
simple covalent
vigorous
so2 structure and ractivity
simple covalent
burns steadily
period 3 and water
form alkaline solutions
10-14 ph
simple ocvalent oxides of sulfur and phosphorus combines with water to form acidic solutions witha ph around 0-2
when in solution these acids dissociate into h+ ions and ions of conjugate base
acid base reaction
ionic oxides react with acid to produce salt and water
neutralisation
acid covalent oxides react with bases to produce a salt and water in a neutralsiation
alumiunm oxide group 3 oxides
partially ionic and covalent
insoluble in water
ions dont dissociate
acts as an acid and base
amphoteric
produce salt and water in neutralisation reactions
sodium vs mag
Both have high melting points, but magnesium has a higher melting point than sodium
This is because of the 2+ charge of magnesium, meaning that it is has a higher charge density
Both are silvery metals
Sodium is quite a soft, silvery metal which tarnishes quickly in air
Magnesium is harder than sodium and you will often see it as magnesium ribbon
mag and water
extremely slow reaction - only a very small number of bubbles
magnesium hydroxide formed will have a pH of around 10 - it is less alkaline than sodium hydroxide because magnesium hydroxide is only partially soluble
Sodium with cold water:
vigorous, exothermic
sodium floats on the surface of the water fizzing rapidly and melting as a result of the heat produced
colourless sodium hydroxide
13-14,
Heated magnesium with steam:
faster than with cold wate
burns with a bright, white flame
magnesium oxide is produced
na and oxygen
heated
vigorous
bright yellow flame
white solid
mg and oxygen
heated
heated
vigorously
bright white flame
white solid
al and oxygen
powdered al
fast
bright white flame
white powder
si and oxygen
powdered si and heat
slowly
bright white sparkles
white powder
p and oxygen
heated
heated
vigorous
yellow or white flame
white clouds
s and oxygen
powdered s heated
gently
blue flame
tpxic fumes
how sulfer tripxide is made
catalyst must be used and the reaction must take place at a very high temperature
The equation for this reaction is:
2S (s) + 3O2 (g) → 2SO3 (g)
Ionic Oxides
Sodium oxide
Magnesium oxide
Aluminium oxide
These are ionic oxides because the bonding exists between metals and non metals
They have giant lattice structures and thus, high melting points
Giant Covalent Oxides
Silicon dioxide
This is covalent because both silicon and oxygen are non metals
The millions of covalent bonds within this giant structure are extremely strong, and thus it has a high melting point
Giant covalent structures can also be called macromolecules or giant molecules
Simple Covalent Oxides
Phosphorus(V) oxide
Sulfur dioxide
Sulfur trioxide
small molecules with only weak intermolecular forces of attraction between them
why so3 has hgher m point
has a slightly higher melting point than sulfur dioxide, SO2, because of the increase in intermolecular forces between the slightly larger SO3 molecules
na properties
solid
high mp
good condcutor
giant ionic
reacts and forms hydroxide ions in sol
13 ph
mg properties
solid
high mp
good conductor
giant ionic
wlightly soluble dsissolved oxide forms a few hydroxide ions
8 ph
al properties
solid
high mp
good conductor
giant ionic
sinoluble but amphoteric
7 ph
si peoperties
solid
very high mp
no conductor
giant
insoluble but acidic
7 ph
p properties
solid
low mp
not conductive
simple
acidic reacts and h+ in sol
2 ph
so2 peoperties
gas
low mp
not conductor
simple
acidic h2so4 few h+ in sol
3 ph
so3 properties
liquid
not conducotr
simple molecule
acidci reacts and forms h2so4
with h+ ions in sol
1 ph
metal oxides and water
Sodium oxide, Na2O, and magnesium oxide, MgO, are made up of ions
They contain an oxide ion, O2-, which is a strong base and will readily produce hydroxide ions through reaction with water
This is why the solutions formed are strongly alkaline
Sodium oxide forms a more alkaline solution than magnesium oxide because it is far more soluble in water
Non-metal oxides
Oxides of phosphorus and sulfur are simple covalent molecules
They will react with water to produce acidic solutions
use of mgo
indeigstion tablers
neutralising excess acids in stomach
Al2O3
Reacts with hot, concentrated alkali to form a salt
SiO2
Reacts with hot, concentrated alkali to form a salt and water
aluminium oxide
mphotenic
Ionic but also partially covalent
Small Electronegativity difference between al and o
Also al is a small ion with high charge so it can get close to the oxide ion and distorts the oxide charge cloud
Alumium metal is protected from corrosion in moist air by a thin layer of Al2o3
Insolubility in water impermeable to air and water
Ionic but binding is too strong to seperste ions
collision theory
must have energy greater than or equal to the activation energy and correct particle orientation
inc temp conc and pressure or maxwell disritubution
shifts ro the right
effect of catalysts of maxwell disrtubtion
shifts to thr left no change on shape
dynamic equillibrium
forward reaction rate is same and remains constant rate to bakcward
closed systems
le chatellier
when a system is subject to change the system will alter to lessen the effect of that change
maximise yield
increasing temp
favours endo
inc yield of endo products
increasing pressures
favours side w fewer moles
increasing conc
favour the reaction that produces the products
hyrodgen oxidation state
+1
oxygen oxidation stte
-2
ha;ogens oxidation state
-1
group 1 metals pxidation state
+1
group 2 atomic radius
increases due to inc shells
reactivity in group 2
increases
inc shielding
ionisation energy
decreases
greater radius
greater sheilding
group 2 melting point
metallic so larger the ions weaker the attractive fordes over greater distance so decrases
group 2 and water
metal hydroxude and hydrogen
alkaline solution
mag reaction reacts very slowly
faster w steam bright whitw flame and powder
solubility of hydroxides
increases down the group
mag hydroxide least soluble
barium hyrdoxide most soluble
mag hydroxide antaxid alaline neitslise acids
solubility of sulfates
decreases
mag most
bar least
barium sulfate used in med
medical tracer
toic if enetr blood stream but insoluble so cannot be abosrbed into blood
metal extraction
magnesium
from titanium chloride via dsiplacement
flue gas removal
calcium oxide and sulfer dioxide
forms calcium sulfite and water
atomic radius in group 7
increase
more shlls
reactivity in group 7
dercreases
additional shielding
atomic radius inc
ionisation energy in group 7
decreases
bpiling point in group 7s
simple covalnt bonds
vdw
strength inc
higher bp
oxidising power in group7
good oxidisng agents
decreases down goup
silver nitratr
anoin halides testes using acified silver nitrat
acidified to remove other impurities that cpuld form a ppt removed
agno3 with cl br i
white ppt
cream ppt
yellow ppt
dilute nhs3 with cl- br- i-
ppt dissolves
no change
no change
conc nh3 with cl- br- i-
ppt dissolves
dissolves
no chnage
sulfate - anioins
bacl2
white ppts
hydroxide anions on litmus paper
red limus ruen blue
carbonate anions
hcl fizz co2
bubbles through limewater
cloudy
calcium
strontium
barium
flames
brick red
red
green
ammonium ions
redd litmus
blue
