atomic structure Flashcards
1
Q
atomic number
A
amount of protons
2
Q
what expression gives mass number
A
proton number plus neutron number
3
Q
expression for proton number
A
mass number- neutron number
4
Q
expression for neutron number
A
mass number - proton number
5
Q
whats mass number
A
neutron number plus proton number
6
Q
atomic mass unit
A
measures weight of atoms 1/12 of carbon 12
7
Q
how to calculate relative mass
A
take isotope and times relative abundance by atomic mass
add together and divide by 100
8
Q
symbol for relative atomic mass
A
Ar
9
Q
whats the relative atomic mass definition
A
the average mass of one atom of an element relative to one twelfth of the mass of carbon 12
10
Q
kinetic energy equation
A
0.5 times mass times velocity squared
11
Q
unit for kinetic energy
A
Joules
12
Q
unit for mass in kinetic energy
A
kg
13
Q
rearranged kinetic energy equation for mass
A
m= 2ke/v squared
14
Q
rearranged equation of kinetic energy for speed
A
v= square root 2ke/m
15
Q
time of flight
A
distance travelled by atom to calculate its mass
16
Q
equation for atoms mass from time of flight
A
m=2ke times t squared/distance aquared
17
Q
rearranging time of flight formula for time subject
A
t= root distance root m/2ke
18
Q
time of flight mass equation for distance subject
A
d= root t times root 2ke/m
19
Q
why do we turn atoms into ions in time of flight
A
because atoms nuetral they need charge to be attracted to charged metal plate
20
Q
what do we need to do so charged plate can give atoms kinetic energy
A
ionise them
21
Q
whats a time of flight mass spectrometer
A
measures time of flight of atom to work our mass of atom
22
Q
4 steps of mass spectrometry
A
-ionisation
-acceleration
-ion drift
-detection
23
Q
electron gun ionisation
A
hot wire that emits electric current which emits fast moving electrons and knocks electron of atom and makes positive charged atom
24
Q
vaporisation
A
to get atoms ready for electron gun they are heated to get ready for electron gun
25
accelaration step
negative charged plate moves positive atom towards it
-atom gains kinetic energy and speed
26
what determines how much energy ion receives
the charge of the atom so big or small all ions have the same kinetic energy as all equal in charge
27
ion drift stage
- hole in negative plate allows ion to move distance down tube
-distance known
-flight tube
-
28
drifting ion
when ion moves through flight tube with known charge and kinetic energy and mass
29
how to get ion to drift
suck all air out of flight tube to allow ion to drift
30
detection stage
when electrons hit negative final plate electric current given off measured by computer
-bigger the current the large the movement
gain an electron
31
how to determine mass of atom in spectrometry
measure time taken to reach detector
32
how to determine number of atoms of particular mass in spectrometry
size of electrical current at detector
33
what happens after detection
computer produces mass spectrum
34
x and y axis of mass spectra
mass/charge ratio and relative abundance
35
how to calculate RAM from mass spectra
identify ions -mass number
-express relative intensity in percentage
-total ions divide by how many of ions your working out times 100 as percentage
-percentage of each times mass number adding individuals up dividing all by 100
36
formula for comparing two ions to predict flight of mass
m1/t2 = m2/t2
37
rearranged equation for comparing two ions flight of mass
t2 = root m2/m1 times t1
38
bohr model of the atom
orbits electron in 3D
at specific distances from nucleus
39
how are electrons quantised
because of fixed distance from nucleus they are restricted to energy levels
40
how to go up energy level or down
lose or gain energy
41
1 way of electron gaining energy
absorbing light
42
why do electrons only absorb specific colours
energy quantised so cant have any energy it likes
-not all colours absorbed
43
good things with bohr rutherford model of atom
- no evidence electrons spiral into nucleus
-uses data to made predictions
-elegant and clear
-good at explaining chemistry
44
schrodingers model of atom
-electrons energy quantised
-energy levels would be exactly values earlier experiment shown
45
how to find electrons energy levels
free electron and find out gaps between jumping from energy level to level
-relative to free electron
46
orbital
space where electrons can be
probability
-where electrons can be most of the time
47
orbitals in first energy level
1
48
orbitals for second energy level
4
49
orbitals for third energy level
9
50
orbitals for fourth energy level
16
51
s sub level orbitals
1
52
p sub level orbitals
3
53
d sub level orbitals
five orbitals
54
f sublevel orbitals
7 orbitals
55
naming sub levels
1s
2s
3s
4s
1p
2p
3p
4p
and so fucking on
56
difference between 2s and 3s sub level
-energy of sub level
-radius of the orbital in the sub level
57
ground state
lowest energy level of atom
58
energy levels with more protons
stronger gaps between levels so stronger attraction
59
energy of atoms when adding more electrons
more gaps and energy levels break down into sub levels
repulsion of electrons
60
order of sub levels
s
p
d
f
61
lowest to highest energy levels order
1s
2s
2p
3s
3p
4s
3d
4p
5s
4d
5p
6s
62
aufbau principle
build up on electron configuration from lowest energy sub levels
63
pauli exclusion principle
an orbital can contain a max of two electrons
64
max electrons for s sub level
2
65
mas electrons for p sub level
6
66
max electrons for d sublevel
10
67
d block of table
group 1 and 2 and hydrogen
68
p block
group 3 4 5 6 7 0
69
d block
all transition elements
70
shorthand electron configurration
element before with added configuration with elements own notation
71
spin
spin up and spin down
72
problem with spin
not electrons spinning but quantam effect
73
rules of spin
pauli says cant have sub level with 2 or more electrons with same spin
74
pauli exclusion principle
no orbital cant have same spin electron
75
hunds rule
-within a sub level every orbital is singly occupied before any doubly occupied
-all electrons in singly occupied orbitals have the same spin
76
why do orbitals in the same level have single spin before they become doubled
-electrons in same orbital repel each other more than electrons in different orbitals
-electrons occupy different orbitals to reduce repulsion
77
find out electron conc of ions
-find number of electrons in ion
-
78
electron conc of cations
remove electrons with highest energy from origional conc
79
electron config of anions
add electrons to original config
80
nuclear charge
how many protons are in nucleus
81
how does nucleus charge effect electrons
larger charge is more
= more protons so more force electrons have on them
82
as you across period how does nuclear charge change
increases by 1
83
nuclear charge change as going down group
increases by more than 1
84
distance from nucleus
-further away less electrostatic force
-weaker force of attraction
-lower energy levels have electrons closer to nucleus
85
protons and distance
higher nuclaeu charge closer each shell is to nucleus
86
what effects the distance between nucleus and outer electrons
nuclear charge and which shell the outer electrons are in
87
distance down group
increases as electrons in different shell so further away fromn nucleus
88
electron electron repulsion effect on electrostatic force on electron
because electrons repel each other that decreases some of force felt by electrons because of protons
89
rules of shielding
-electron closer to nucleus shields charge of one proton
-electron in same shell shields small amount of one proton
-electron further in shell doesnt shield at all
90
moving across period for shielding
number of outer electrons increases so shielding increases
91
down group shielding
increases because new shell made
92
factors that effect forces on electrons
-nuclear charge
-distance from nucleus
-shielding
93
group 1 elements and water
-electrons removed
-higher energy level equals less energy to move
-moves from highest energy sublevel
94
first ionisation energy
the energy required to remove one mole of electrons from one mole of gaseous atoms of element
95
unit for ionisation energy
KJ/ mole
96
first ionisation energy equation
element(g) + element ion (g) + e-
97
first ionisation energy down a group
decrease down group
-attraction to nucleus decreases
98
first ionisation energy across period
--increases
-nuclear charge increases
-harder to remove electrons
-generally increases
99
why do ionisation energies decrease down group
-weaker attraction to nucleus
-outer electrons more shielded and further away from nucleus
-
100
why first ionisation energy across period generally increases
-nuclear charge increases
-shielding of outer electrons stays roughly the same
-strong attraction to nucleus
101
why does potassium have lower ionisation energy than sodium
potassiums outer electron more shielded and further away from nucleus
weaker attraction to nucleus
102
why does magnesium have higher ionisation energy than sodium
-magneisum gas higher nuclear charge than sodium and both atoms have same shielding since in same shell
-masgnesiums outer shell electrons have stronger force of attraction to nucleus than sodium
103
magnesium and aluminium first ionisation energies
-Al has lower first ionisation energy than magnesium
-Al electron removed from 3p but Mg from 3s
-3p sublevel further away from nucleus and also shielded by aluminiums 3s electrons
-less energy to remove electron from AL
-
104
phosphorus and sulfur ionisation energies
-sulfur has paired electron in 3p sublevel
-electron repulsion between pairs
-less energy needed
105
second and so forth ionisation energy
removing second and whatnot electrons from ions
106
successive ionisation energies
-always increasing
-in certian points bigger jumps
107
second ionisation energy deifnition
the energy required of an element to remove one mole of electrons from one mole of gaseous 2+ ions of that element
108
why do successive ionisation energies always increase
because electrons are removed from a increasingly positive ion which requires more energy
109
how do graphs of successive ionisation energies give evidence for shells
-big jumps give evidence for shells
-we can explain jumps by saying electron is being removed from an inner shell
110
how does graph of first ionisation energy across period give evidence for subshells
-drop between al and mg on graph give us evidence
-Al has greater nuclear charge than mg so first ionisation would be greater
Al lower than mg so Al outer electorn in different sublevel
111
how does graph of first ionisation energy across period give evidence that electrons in same orbital repel more than electrons in different orbital
-drop between P and S
-sulfur has greater nuclear charge than P
-sulfur isnt higher than P so idea that electrons in same orbital repel each toher more
112
rutherford and current model difference
-current model has neutrons and protons but rutherfords doesnt
-current model shows electrons in different energy levels- rutherfords doesnt
113
missing percentage abundance
add al known percentages and take away from one hundred
114
equation for electrospray ionisation
X(g) + H+ → XH+(g)
115
define mass number of an atom
number of protons and neutrons in nucleus of atom
116
finding number of neutrons
take away top number from proton number
117
number of protons same as
number of electrons
118
define relative atomic mass
average mass of an atom of an element compared to 1/12 the mass of carbon 12 atom
119
working out RAM when given relative intensities
add all intensities up and divide by total number
120
why you need to ionise atoms before doing time of flight
-ions will interact with and be accelerated by electrical current
-ions create current when hitting detector
121
describe how molecules are ionised using electrospray
-sample dissolved in volatile substance
-injected through needle at high positive charge
-each molecule gains a proton
122
explain first ionisation energies pattern from lithium to neon
general trend li to ne
-first ie increases
-more protons
-electrons in same shell
-no extra shielding
-stronger attraction between nucleus and outer electrons
deviation be - B
-B lower than Be
-outer electron in 2p
-higher in energy than 2s
deciation N to O
-O lower than N
-2 electrons needed in 2p to pair
-pairing electrons cause repulsion
123
role of water with calcium reaction
oxidising agent
124
trend in group 2 first ionisation energies
-decrease
-ions get bigger
-weaker attraction of ion to lost electron
125
electron impact ionisation
sample bombarded with high energy electrons
-sample of molecules lose electron forming positive ion
126
how TOF separates two species to give peaks
-positive ions accelerated by electric field
-to constant kinetic energy
-all have same kinetic energy
-so lower mass ratio move faster
127
how to predict m/z ratios on graph
add all possibilities of all isotopes added up
2 combinations
128
how to work out relative intensity of peaks
work out probability of each isotope in each combination and put into fraction and times fractions
129
small peaks on mass spectra
caused by fragmenting of molecules with electron gun
130
