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