atomic structure

Question 1

what is the tof spectrometer

Answer 1

Detects the mass and relative abundance of isotopes

Question 2

what are the 3 steps of using a tof mass spectrometer

Answer 2

ionisation, acceleration, detection

Question 3

two types of ionisation

Answer 3

Electron impact:

Sample vapourised X_(g)

Bombarded with electrons from electron gun

X_(g)+ e^- => X⁺_(g)+ 2e^-

Electro spray

Sample dissolved in a volatile solvent

Turned into a fine spay via a charged needle (increases the m/z value by 1)

H+ gained from a solvent

X_(g)+ H⁺ => XH⁺_(g)

Question 4

what happens during acceleration

Answer 4

Charged plates create an electric field

All ions accelerated forwards with the same kinetic energy (ion drift)

Have diff types velocities due to differences in mass

(More mass=less velocity)

Question 5

what happens during detection

Answer 5

Negatively charged detector

Positive ions gain electrons at the plate, which cause an electric current

The current is monitored to give a spectra

Question 6

what is a mass spectra

Answer 6

a graph that shows the relative abundances of the different isotopes (and their masses)

Question 7

what is symbol for isotopic mass

Answer 7

m/z

(mass: charge ratio)

Question 8

how to calculate isoptopic mass

Answer 8

find A_r

sum of isotopic mass*percentage

all divideby 100

Question 9

how to calculate unknown isotopic mass

Answer 9

Question 10

what else may show up in a mass spectrum?

Answer 10

very small peaks at Mr+1 made up of elemental molecules

i.e ¹³C and ²H

(only organic molecules)

Question 11

how to find ratios of different isotopes forming

Answer 11

Question 12

velocity calculations

(3 formulae need to be used)

Answer 12

KE= 1/2mv² (rearrange to find v)

convert the grams of the mass of the ion to kg

d=tv (finds length of flight tube)

Question 13

what are electron orbitals

Answer 13

where electrons are found, within energy levels

Question 14

order of orbitals (low to high)

Answer 14

s, p, d, f

Question 15

how many electrons does an orbital hold

Answer 15

2

Question 16

what is s orbital

Answer 16

spherical in shape, holds up to 2

Question 17

what is p orbital

Answer 17

figure 8 shape

found in groups of 3 orbitals

Question 18

what is d orbital

Answer 18

various shapes

found in groups of 5 orbitals

∴ holds up to 10 electrons

Question 19

what orbitals are in each energy level

Answer 19

Energy level 1: 1s²

Total e:2

Energy level 2: 2s²,2p⁶

Total e:8

Energy level 3: 3s²,3p⁶,3d¹⁰

Total e:18

Energy level 4: 4s²,4p⁶,4d¹⁰,4f¹⁴

Total e: 32

Question 20

what is hund’s rule

Answer 20

electrons occupy empty orbitals b4 pairing b/c minimises repulsion

∴

Question 21

what does it means to be isoelectric

Answer 21

means that ions has the same configurstion as some noble gas

Question 22

exception to orbital energy levels

Answer 22

found in transition metals where 4s is filled in before 3d and electrons lost from 4s before 3d

Question 23

what is first molar ionisation energy

Answer 23

(making 1+ ions)

The energy required to remove one mole of electrons from 1 mole of the gaseous atoms

X_(g) => X⁺_(g) + e^-

Question 24

what is 1st IE dependant on

Answer 24

Nuclear charge more = increase IE

Shielding more = decrease in IE

Distance more = decrease in IE

Question 25

what are the trends of 1st IE as it goes down a group

Answer 25

decrease ## Footnote Because nuclear charge increases, however shielding sand distance of the e from the nucleus increases Which lowers the effective charge on the nucleus Decreases the attraction between the nucleus and outer e Lowers the energy required to remove the outer e

Question 26

what are the trends of 1st IE going across a period

Answer 26

general increase ## Footnote As nuclear charge increases, there is no change in the amount of shielding/ distance of the outer e from the nucleus Attraction between the outer e and nucleus increases more energy need to remove the e

Question 27

what are the exceptions to trends of 1st IE going across a period

Answer 27

between group 2/3 EG. Be/B This is because the outer electron in B is in the 2p electron orbitals and the outer e in Be is in 2s orbital The e in the 2p orbital has the higher e Therefore is required to remove it AND between groups 5/6 EG N/O The outer e in O is paired with another in the 2p orbital the outer electron in N is not paired Repulsion between the paired electrons in o means that less energy is required to remove it This is because e it is easiest remove due to shielding makes a full s orbital Easier to remove due to repulsion between paired e

Question 28

what is successive ionisation energy

Answer 28

the energy required to remove es one y one from the same atom Eg. 2nd ie : X⁺_(g) =\> X²⁺_(g) + e^- 3rd ie: X²⁺_(g) =\> X³⁺_(g) + e^-

Question 29

what is trend of successive ionisation energies

Answer 29

General increase in ie due to increasing effective charge on the nucleus

Question 30

describe what is going on in these photos and how to figure out which group of elements the graph is describing

Answer 30

Large jumps caused by the e being taken from an energy level that’s closer to the nucleus ie DECREASED distance + DECREASED shielding Therefore stronger attraction Pattern in group 1: large jump between successive ie 1+2 group 2: large jump between successive ie 2+3 etc...