3.1.1 Atomic Structure Flashcards
what is the relative charge of a proton?
+1
what is the mass of a proton?
1
what is the relative charge of an electron?
-1
what is the relative mass of an electron
1/1836
what is the relative charge of a neutron?
0
what is the relative mass of a neutron?
1
what does the nucleus of an atom contain?
protons
neutrons
what orbits around an atom?
electrons
what is the force of attraction held between protons and neutrons?
nuclear force
what is the force present between protons and electrons?
electrostatic force
what is the relative charge of an atom of an element?
neutral
what letter is the mass number represented by?
A
what letter is the atomic number presented as?
Z
what is the atomic number?
the number of protons+electrons
what is the mass number?
total number of neutrons and protons in a nucleus
how can you find the number of neutrons?
mass number - atomic number
what are the stages of time of flight mass spectrometer
ionisation
acceleration
ion drift
ion detection
data analysis
why is the sample held within a vacuum
so that arent react with the gases in the atmosphere.
what occurs during ionisation. (TOF)
converts the atoms to positive ions by knocking off an electron.
what is electrospray ionisation?
sample is placed in a volatile solvent
is forced through a fine needle: giving fine mist/aeorsal
tip of needle has high voltage
sample gains a proton H+
what is electron impact?
electron gun forces high energy electron towards sample
knocks out an electron
forms positive ion
what is the general formula of an atom losing an electron
1st ionisation energy
X(g)–> X+(g) + e-
what happens when the ions are attracted to negatively charged plate?
they accelerate towards the plate
what is the kinetic energy of the ions
it is constant.
will smaller ions have a greater speed
yes
what is speed of the ions in the ion drift?
smaller ions move faster
larger ions move slower
what occurs during ion detection?
the ions pick up an electron
which causes a current to flow
what does the flow of current represent?
size of current is proportional to the abundance of the isotope
what happens when a molecule interacts with electron impact?
causes fragmentation
what is the mass spectrometer used for?
relative abundance of isotopes
relative isotopic mass
how can we find the relative isotopic mass
isotopic mass*relative abundance / total relative abundance
what are the names of the sub shells/ orbitals
s,p,d,f
how many electrons does a s-orbital hold?
2
how many electrons does the p orbital hold
6
how many electrons does the d orbital hold?
10
what is the first ionisation energy?
energy required to remove 1 mole of an electron from a mole of atoms in its gaseous state
measured in kJ/mol
what is an example of the 2nd ionisation energy?
X+ –> X2+ +2e-
what factors affect ionisation energy?
nuclear charge
atomic radius
shielding
what is the trend in ionisation energy in period 3
increases
-across the group nuclear charge increases (proton no. IN)
-electrons have greater attraction to +ve nucleus
-decreases atomic radius
-same orbitals
how does sulfur deviate from the trend in ionisation energy?
DECREASES
electrons are paired in the same p orbital
repulsion between them
less energy required to break forces
what is the trend in first ionisation energies as you go down the group?
DECREASES
atomic radius increases
outermost electron further away from nucleus
more shielding
weaker attraction to nucleus.
what is the relative atomic mass
the average mass of an atom compared to 1/12 of the mass of the atom carbon.
in what ways are isotopes the same?
same electronic configuration.
