number of protons in the nucleus,
also equal number of electrons
mass number
number of protons and neutrons in a nucleus
isotopes of atoms
atoms of the same element with the same
number of protons but different number of
neutrons, they still have the same chemical
properties because the number of electrons
on the outer shiel is still the same. its just
mass that varies
relative charge
change of particles relative to
the electron ( like that of the electron)
relative mass
mass of a particle 1/12 mass of 1 atom of c12
mass spectrometer
to separate ions with
different masses, and
helps identify complex
molecules
steps in mass spectrometry
1.vaporisation
sample must be in a gaseous state
2.ionisation
electron gun fires high energy electron at gaseous
molecule eg m(g)+e- --> m*(g) = 2e-
3.acceleration
ions are accelerated by an
electrical field which then
focus into beams to pass
through slits
4.deflecrion
beam of ions are deflected by a strong magnetic field,
magnitude depends on m/z ratio the smaller the m/z the
larger the deflection
5.detection
the ions are directed to the detector by a
different magnetic field the ions hit the
detector and create a small electric current
the bigger the current the ore of the ion
there is the current is amplifies and sent o
computer to analyse = create spectrum
the number of peaks created on the
spectrum = the amount of isotopes m/z of
peaks= mass of ion and hight= amount of
each isotope
atomic mass from mass spectrum data equation
Ar= (sum) relative mass of isotope x
abundance of isotope
molecular mass Mr
from spectrum=
peak with highest
value = Mr
definition of atomic mass = Ar =
mean mass of 2 atom / 1/12 of the
mass of c-12
definition of relative
molecula mass of an
entity
Mr= mean mass of entity/ 1/12
mass of 1 atom of c-12
enitity =molecule e.g CH4 or NaCl
Mr from formula
sum of relative
atomic masses of
all atoms in
formula
electron configuration
electron arrangement in atom
found in shells, lower energy are closer to nucleus
Kr
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
for element up to Kr
element fill in the
order of Kr except
Cr;4s1 3d5 and Cu;4s1
3d10
cations +
ins removed in reverse order except 4s
and 3d
atomic orbitals
maximum of
2 electrons in
opposite spin
and are
represented
as up an
down arrows
definaition of first ionisation energy
energy required to remove 1 mole of
electron from 1 mol of gaseous atom
first I.E equation... M(g) __>M=(g)=e-
1st I.E DOWN a group= decreases
because the outer electron have more
shielding from the attraction from the
nucleus because its further away
ACROSS a period=
general increase
because number of
protons create
increasing nuclear
attraction while the
outer electrons in
same energy levels =
similar shielding from
nucleus
second I.E equation..M(g)__>m2=(g)+e-
gp 2 and gp 3
gp 3 outer electrons are easier to remove than gp 2 because
gp 2 outer electrons is 2s or 3s and gp 3 are higher level 2p
or 3p = more shielding
gp 5 and gp 6
gp 6 outer electrons easier to remove than gp 5
outer electron in same sub level 2p or 3p but gp6
outer electron p4 is paired and mutual repulsion
occurs