3.1.1 atomic structure

Question 1

history of the atom

Answer 1

lol

Question 2

what happens when an e- gains/loses energy

Answer 2

when an e- gains energy it gets excited and moves to a higher energy level. when it loses energy it relaxes to its ground state

Question 3

anion

Answer 3

+ve ion

Question 4

cation

Answer 4

-ve ion

Question 5

isotope

Answer 5

atom of an element with the same number of protons and a different number of neutrons

(you can have ions of isotopes)

Question 6

why do isotopes of they same element have the same chemical properties

Answer 6

because they have the same electron configuration/ number of e-

Question 7

why do isotopes of the same element have different physical properties

Answer 7

bc they each have a different number of neutrons.

isotopes with more neutrons have
1. higher mass
2. higher density
3. higher m/b points
4. slower diffusion rates

Question 8

relative atomic mass

how is it calculated

Answer 8

average mass of an atom of an element to 1/12 the mass of a C12 atom

using abundance of isotopes

Question 9

what is an energy level

Answer 9

specific orbits which electrons occupy as they orbit around the nucleus

each energy level represents a specific energy value

each energy level contains a different number of electrons

as you go further out energy values are higher

Question 10

what is a sublevel

Answer 10

energy levels can be broken down into sublevels: s, p, d etc.
energy level one only has s
el 2 has s and p
el 3 has s, p, d

Question 11

what is an orbital

Answer 11

sublevels can be broken down into orbitals. these are basically areas where electrons probably occupy. there are max 2 electrons in each orbital

the s sublevel has 1 orbital, so 2 e-
the p sublevel has 3 orbitals; 6
the d sublevel has 5 orbitals; 10

Question 12

why does 4s fill before 3d

Answer 12

as we go further out from the nucleus the sublevels overlap more and more. 4s is actually of lower energy than 3d. according do Aufbau principle, electrons fill the lowest energy orbitals. once it fills it’s of higher energy.

the diagonal rule can be used to identify which sublevels come next

Question 13

two types of representing electron configuration

Answer 13

standard

and short structure, where you use the nearest noble gas in square brackets then add the extra e-

Question 14

what are two special cases of e- configuration

Answer 14

chromium

copper

Question 15

special case of chromium

Answer 15

should be the standard configuration but instead it ends in
4s13d5

because electron is demoted from 4s to 3d because atoms are more stable with a half set of orbitals

Question 16

special case of copper

Answer 16

should be the standard configuration but instead it ends in
4s13d10

because electron is demoted from 4s to 3d as the atom is more stable with a full set of 3d orbitals

Question 17

ionisation energy

Answer 17

energy required to remove one mole of electrons from one mole of atoms in gaseous state

Question 18

units of IE

Answer 18

KJmol^-1

Question 19

why is the reaction of IE endothermic

Answer 19

energy needs to be taken in by the outer e- being removed to overcome the eFoA between the nucleus and itself

Question 20

def 2nd IE

Answer 20

energy required to remove one mole of electrons from +1 ions (!!) in a gaseous state

Question 21

how can we quickly form the IE equation for different IEs?

Answer 21

nth IE ;

then the product of the reaction is +n charge

Question 22

why is 1st IE the lowest value always

Answer 22

eFoA is stronger in +ve ions compared to a less positive or neutral atom because there is more positive acting on the outer e-

each time requires more energy; you’re trying to remove from an increasingly +ve ion

Question 23

what are successive ionisation energies

Answer 23

they are the IEs (in KJmol^-1) to remove successive electrons from the same atom

results can be logged on a graph and conclusions have been made for it

Question 24

what can be observed from a graph depicting successive IEs?

Answer 24

1. different electrons require different amounts of energy to be removed
2. graph is not linear
3. jumps in the graph (indicate energy levels)

Question 25

how do jumps in the successive IE graph show existence of energy levels

what do the gradual increase lines mean

Answer 25

in a jump from X to y, the y electron must be significantly closer to the nucleus bc there is a significant amount of energy it needs more than X electron.

expected bc ion is increasingly+ve

Question 26

how can you tell group number from successive IE data

how can you tell period number

Answer 26

identify big jumps in the numbers

group number = e- in outer energy level

however many electrons before 1st jump = group number

period number is no. energy levels.
n+1 rule: no. energy levels is the no. jumps add 1

Question 27

what happens to IE value down a group

Answer 27

it decreases

Question 28

what factors affect the strength of the eFoA between the nucleus and outer e-

Answer 28

nuclear charge

distance between the nucleus and outer e-; atomic radius

shielding

Question 29

why does IE decrease down a group

Answer 29

nuclear charge increases but this is offset by the
1. increase in atomic radius due to more completed energy levels making the electron further away from the nucleus therefore decreased FoA

2. increase in shielding because there are more completed energy levels which weakens the FoA

Question 30

what does the trend of group IE decreasing show

Answer 30

probes that the outer e- as you go down must be further away and with more shielding

we would expect it to be greater and greater due to the increased nuclear charge. so the fact it decreases indicates the presence of energy levels, causing this effect of atomic radius and shielding

Question 31

what is the trend in IE across a period

Answer 31

it increases overall

Question 32

what is the reason for the trend in IEs across a period

Answer 32

there is a negligible increase in shielding because sublevels are being filled

there is an increase in nuclear charge so the eFoA increases, making the overcoming of that require more energy

there is a DECREASE in atomic radius because nuclei are better at attracting e-s (more protons). so increased FoA; the e- cloud is slightly closer.

Question 33

where are the deviations from the overall trend in IE across a period

why?

Answer 33

groups 2 -> 3
outer e- is being removed from an orbital of higher energy (be specific in questions) so less energy is needed to remove it.

groups 5 -> 6
there is a pairing of e-s in the orbital of gr6 atoms where there isn’t in gr5. so electron repulsion. less energy needed to remove it

Question 34

what does this give evidence for ?

Answer 34

the deviations can be explained by the existence of energy levels, sublevels and orbitals

Question 35

how to compare IEs

Answer 35

make sure know the e- configuration for whatever is brings asked, atom or ion

who has a smaller atomic radius?
who has more shielding?
which orbital is outer e-?
who has higher nuclear charge?
which main energy level?

Question 36

what is TOF mass spectrometry

Answer 36

? Girl beats me

Question 37

what’s the abbreviated process

Answer 37

VIA DD

vaporisation
ionisation
acceleration
drift
detection

Question 38

in vaporisation…

Answer 38

substance is made into a gas bc . needs to

Question 39

in ionisation…

Answer 39

the particles are made to have +ve charges because that is the only way they can be accelerated and detected.

they can have this done in two ways:

electron impact
or electrospray

Question 40

electron impact

Answer 40

high energy electrons are fired from an electron gun at the sample. knocks off an electron and results in a +1 charge

this is usually done for

Question 41

electrospray

Answer 41

dissolve sample in polar volatile solvent;
inject through a fine hypodermic needle to give a fine mist;
top of needle has a high voltage;
gains a proton as it leaves the needle

charged sample moves toward -ve plate and repel as they get closer so a stream of charged particles is produced

Question 42

in acceleration…

Answer 42

ions are accelerates using an electric field so ions all have the same kinetic energy. they are headed towards a -vely charged plate.

heavier ions will have slower velocity, therefore hit the detector plate later. so different mass ions have different times of flight

Question 43

in drift…

Answer 43

ions passing through the flight tube (vacuum so doesn’t hit air particles) towards detector.

time of flight determines the mass of the ion (have the KE, the distance and now the time)

Question 44

equation for determining mass of ion with tof ms

Answer 44

t= d√(m/2ke)

time, s
distance (of flight tube), m
mass, kg
ke, J

Question 45

in detection…

Answer 45

electron transfers from the detector to the +be ion when the ion hits it. this induced a current. the size of this current tells us the abundance of that ion because they will all hit at same time (same mass so same tof)

how many different currents you get (or at different times idk?) tells you the number of isotopes. the size for the current is proportional to abundance of that isotope.

Question 46

if electrospray is used, when reading a m/z graph we need to

Answer 46

take away 1 from mass reading because a proton has been added

Question 47

reasonably sized peaks on an m/z graph indicate

Answer 47

an isotope

Question 48

m/z graphs shows the

Answer 48

relative abundance (obtained from current) of different isotopes of an element sample

Question 49

m+1 peaks

Answer 49

for molecules, small peaks to the right of the main peak showing molecular mass are due to there being different isotopes of elements used in the molecules eg C13 instead of C12 and H2 instead of H1

Question 50

the Mr of a compound from a graph

Answer 50

the leak with the greatest (!) m/z value ignoring m+1 peaks. this is the molecular ion peak