atomic structure Flashcards
write an example of an ionisation equation
k(g)—>k+(g)+e-
why is the outer most electron the highest energy electron
it is furthest from the nucleus
why does 4s fill up before 3d
4s has lower energy
electrons fill up in lower energy order
what is the atomic number
number of protons
what is the atomic mass
number of neutrons + protons
what is a positive ion
cation
has lost electrons and has more protons that electrons
what is a negative ion
anion
has gained electrons and has more electrons that protons
what is a isotope
atoms of the element which have the same number of protons but different number of neutrons
what factors affect ionisation energy
-nuclear charge(number of protons in the nucleus)-more protons, stronger electrostatic attraction between nucleus and outermost electron so there is more energy needed to remove the outer most electron.
-shielding-electrons on a shell further away from the nucleus means there is more shielding, weaker electrostatic attraction so less energy needed to remove outermost electron.
what does the mass spectrometer measure
-relative abundance
-mass/charge ratio (m/z)
what do jumps in ionisation energy mean
jumps in values of consecutive ionisation energy means that the electron with a higher ionisation energy is being removed from a shell closer to the nucleus so it has a stronger electrostatic attraction and there is a big difference in its ionisation energy compared to the one before.
what are the units of ionisation energy
kj/mol
trends in first IE across a period
atomic radius decreases - higher proton number so higher electrostatic attraction between nucleus and outermost electron
-higher first ionisation energy
time of flight equation
t=d/v
t=time (sec)
v=velocity of ion(m/s)
d= distance or length of flight tube (m)
shape of s and p orbital
s= sphere
p=dumbbell shape with a cross
results of a TOF mass spectrometer
if a single element is injected into a mass spectrometer it will be sperated into its isotopes
each peak is an isotope and height of the peak is the relative abundance of each isotope
number of electrons in each shell
1-2
2-8
3-18
4-32
kinetic energy equation
KE=1/2mv^2
kinetic energy is the energy that objects possess due to their motion
m=mass(kg)
v=velocity(m/s)
KE=kinetic energy(J)
isotopes have the same chemical properties because..
they have the same electronic configuration
how to calculate Ar
sum of (isotope abundance x isotope mass number)/sum of (isotope abundance)
how many orbitals does each subshell have
S-1
P-3
D-5
F-7
each orbital holds 2 electrons
exceptions of ‘normal’ electronic configuration
chromium and copper
electrospray
sample is dissolved in volatile solvent and injected through a fine hypodermic needle to give a fine mist
tip of the needle is attatched to a positive terminal
particles gain a proton
x(g) + H+——->xH+(g)
used on higher molecular mass subtances
electron impact
sample analysed is vapourised and high energy electrons are fired at it which come from an ‘electron gun’ - hot wire filament
knocks off an electron to form a 1+ ion
x(g)—>x+(g)+e-
used on substances with low formula mass
draw and label the stages of a mass spectrometer
1-ionisation-2 methods but in both the sample particles get a positive charge
2-acceleration-postive ions are attracted towards the negative plate and accelerate towards it. Once accelerates all ions have the same kinetic energy
3-ion drift-ions drift towards the detector the speed they reach teh detector depends on their size
smaller ions reach faster and larger ions take longer
4-detector-each ion gains an electron then a current is generated which is proportional to the abundance of ions
5-analysis-signal from detector is passed to computer which generates a mass spectrum
deviations in ionisation energy
3rd element-
The first e- removed from (element before) is from a 2s sub level
The first e- removed from(element) is from a 2p sub level
2s sub level is lower in energy than 2p so less energy needed to remove e- from (element)
6th element-
The first e- removed from(element before) is from a 2p sub level and is unpaired
The first e- removed from (element) is from a 2p sublevel and is paired
(element) has lower ionisation energy due electron paired repulsion so needs less energy to remove the electron
describe the bohr model
-protons and neutrons inside the nucleus and can be called nucleons
-electrons orbit the nucleus in shells or energy levels
describe rutherfords test
he fired He2+ ions at a sheet of gold foil
when the ions arrived at point p he concluded that most of the atom is empty space
some ions were deflected to point q and so he concluded that an atom must have a small positive nucleus
definition: ionisation energy
the amount of energy needed to remove a mole of electrons from a mole of atoms in a gaseous state
attraction rules to compare the size and IE’s of different elements
-write electronic configuration
-write number of protons
-compare shielding
if its the same compare number of protons
-compare attraction between nucleus and outer electron
